From c241ecdc14b4bb4e50c48029ed94136664afb6a7 Mon Sep 17 00:00:00 2001
From: Marcelo Vani <marcellovani@yahoo.co.uk>
Date: Thu, 29 Nov 2018 13:16:39 +0000
Subject: [PATCH 01/17] Use composer instead of submodules

---
 .gitmodules   |  4 ----
 Gruntfile.js  |  2 +-
 composer.json |  3 ++-
 composer.lock | 47 +++++++++++++++++++++++++++++++++++++++++++----
 phpcs.xml     |  1 -
 5 files changed, 46 insertions(+), 11 deletions(-)
 delete mode 100644 .gitmodules

diff --git a/.gitmodules b/.gitmodules
deleted file mode 100644
index a2da7e17ea5..00000000000
--- a/.gitmodules
+++ /dev/null
@@ -1,4 +0,0 @@
-[submodule "dev-lib"]
-	path = dev-lib
-	url = https://github.com/xwp/wp-dev-lib.git
-	branch = master
diff --git a/Gruntfile.js b/Gruntfile.js
index 725b78af2a1..0d4c36cc63a 100644
--- a/Gruntfile.js
+++ b/Gruntfile.js
@@ -34,7 +34,7 @@ module.exports = function( grunt ) {
 				stderr: true
 			},
 			readme: {
-				command: './dev-lib/generate-markdown-readme' // Generate the readme.md.
+				command: './vendor/xwp/wp-dev-lib/generate-markdown-readme' // Generate the readme.md.
 			},
 			phpunit: {
 				command: 'phpunit'
diff --git a/composer.json b/composer.json
index c13e765d545..ca15ebd0c16 100644
--- a/composer.json
+++ b/composer.json
@@ -12,7 +12,8 @@
     ],
     "require": {
         "php": "^5.3.6 || ^7.0",
-        "sabberworm/php-css-parser": "dev-master"
+        "sabberworm/php-css-parser": "dev-master",
+        "xwp/wp-dev-lib": "dev-master"
     },
     "require-dev": {
         "wp-coding-standards/wpcs": "^0.14.0",
diff --git a/composer.lock b/composer.lock
index 382e098823c..83eed3b1af4 100644
--- a/composer.lock
+++ b/composer.lock
@@ -1,10 +1,10 @@
 {
     "_readme": [
         "This file locks the dependencies of your project to a known state",
-        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
+        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "33d4c9d9bf48285e6557d79a6b4b7601",
+    "content-hash": "712d01725ebb02474abc18782e3de7ac",
     "packages": [
         {
             "name": "sabberworm/php-css-parser",
@@ -50,7 +50,45 @@
             "support": {
                 "source": "https://github.com/xwp/PHP-CSS-Parser/tree/master"
             },
-            "time": "2018-11-25 04:50:29"
+            "time": "2018-11-25T04:50:29+00:00"
+        },
+        {
+            "name": "xwp/wp-dev-lib",
+            "version": "dev-master",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/xwp/wp-dev-lib.git",
+                "reference": "ff2cfd2dfbf42360d70b38089d31eaeefd715146"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/xwp/wp-dev-lib/zipball/ff2cfd2dfbf42360d70b38089d31eaeefd715146",
+                "reference": "ff2cfd2dfbf42360d70b38089d31eaeefd715146",
+                "shasum": ""
+            },
+            "type": "library",
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Weston Ruter",
+                    "email": "weston@xwp.co",
+                    "homepage": "https://weston.ruter.net"
+                },
+                {
+                    "name": "XWP",
+                    "email": "engage@xwp.co",
+                    "homepage": "https://xwp.co"
+                }
+            ],
+            "description": "Common code used during development of WordPress plugins and themes",
+            "homepage": "https://github.com/xwp/wp-dev-lib",
+            "keywords": [
+                "wordpress"
+            ],
+            "time": "2018-11-22T04:47:01+00:00"
         }
     ],
     "packages-dev": [
@@ -270,7 +308,8 @@
     "aliases": [],
     "minimum-stability": "stable",
     "stability-flags": {
-        "sabberworm/php-css-parser": 20
+        "sabberworm/php-css-parser": 20,
+        "xwp/wp-dev-lib": 20
     },
     "prefer-stable": false,
     "prefer-lowest": false,
diff --git a/phpcs.xml b/phpcs.xml
index ef3a5c5b010..87fa0be5872 100644
--- a/phpcs.xml
+++ b/phpcs.xml
@@ -42,7 +42,6 @@
 	<arg name="extensions" value="php"/>
 	<file>.</file>
 
-	<exclude-pattern>*/dev-lib/*</exclude-pattern>
 	<exclude-pattern>*/node_modules/*</exclude-pattern>
 	<exclude-pattern>*/vendor/*</exclude-pattern>
 	<exclude-pattern>includes/lib/*</exclude-pattern>

From 82b4767992f700509327481f9ae62910e9cde958 Mon Sep 17 00:00:00 2001
From: Marcelo Vani <marcellovani@yahoo.co.uk>
Date: Thu, 29 Nov 2018 13:17:07 +0000
Subject: [PATCH 02/17] Deleted folder

---
 dev-lib | 1 -
 1 file changed, 1 deletion(-)
 delete mode 160000 dev-lib

diff --git a/dev-lib b/dev-lib
deleted file mode 160000
index e5c56ae4401..00000000000
--- a/dev-lib
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit e5c56ae44013f5f056ba97f35bd060a2b49e12f3

From e91bc1522251d0caf60fba8e07455b000005b625 Mon Sep 17 00:00:00 2001
From: Marcelo Vani <marcellovani@yahoo.co.uk>
Date: Thu, 29 Nov 2018 13:35:44 +0000
Subject: [PATCH 03/17] Updated folder

---
 .travis.yml     |  2 +-
 Gruntfile.js    |  2 +-
 contributing.md | 13 +++++++++----
 phpunit.xml     |  3 +--
 4 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index ad755016ee4..387d02f91ff 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -20,7 +20,7 @@ cache:
 install:
   - if [[ $DEV_LIB_SKIP =~ composer ]]; then composer install --no-dev; fi
   - nvm install 8.11.4 && nvm use 8.11.4
-  - export DEV_LIB_PATH=dev-lib
+  - export DEV_LIB_PATH=vendor/xwp/wp-dev-lib
   - source $DEV_LIB_PATH/travis.install.sh
 
 script:
diff --git a/Gruntfile.js b/Gruntfile.js
index 0d4c36cc63a..18c7d5defdc 100644
--- a/Gruntfile.js
+++ b/Gruntfile.js
@@ -113,7 +113,7 @@ module.exports = function( grunt ) {
 			versionAppend = new Date().toISOString().replace( /\.\d+/, '' ).replace( /-|:/g, '' ) + '-' + commitHash;
 
 			paths = lsOutput.trim().split( /\n/ ).filter( function( file ) {
-				return ! /^(blocks|\.|bin|([^/]+)+\.(md|json|xml)|Gruntfile\.js|tests|wp-assets|dev-lib|readme\.md|composer\..*|webpack.*|languages\/README.*)/.test( file );
+				return ! /^(blocks|\.|bin|([^/]+)+\.(md|json|xml)|Gruntfile\.js|tests|wp-assets|readme\.md|composer\..*|webpack.*|languages\/README.*)/.test( file );
 			} );
 			paths.push( 'vendor/autoload.php' );
 			paths.push( 'assets/js/*-compiled.js' );
diff --git a/contributing.md b/contributing.md
index 95c5e419e5b..e24cf27af32 100644
--- a/contributing.md
+++ b/contributing.md
@@ -5,14 +5,19 @@ Thanks for taking the time to contribute!
 To start, clone this repository into your WordPress install being used for development:
 
 ```bash
-cd wp-content/plugins && git clone --recursive git@github.com:Automattic/amp-wp.git amp
+cd wp-content/plugins && git clone git@github.com:Automattic/amp-wp.git amp
 ```
 
-If you happened to have cloned without `--recursive` previously, please do `git submodule update --init` to ensure the [dev-lib](https://github.com/xwp/wp-dev-lib/) submodule is available for development.
+### Build dependencies with [Composer](https://getcomposer.org)
 
-Lastly, to get the plugin running in your WordPress install, run `composer install` and then activate the plugin via the WordPress dashboard or `wp plugin activate amp`.
+```bash
+cd amp
+composer install
+```
+
+Lastly, activate the plugin via the WordPress dashboard or `wp plugin activate amp`.
 
-To install the `pre-commit` hook, do `bash dev-lib/install-pre-commit-hook.sh`.
+To install the `pre-commit` hook, do `bash vendor/xwp/wp-dev-lib/install-pre-commit-hook.sh`.
 
 Note that pull requests will be checked against [WordPress-Coding-Standards](https://github.com/WordPress-Coding-Standards/WordPress-Coding-Standards) with PHPCS, and for JavaScript linting is done with ESLint and (for now) JSCS and JSHint.
 
diff --git a/phpunit.xml b/phpunit.xml
index a1b4d099ded..eee736f3ee1 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -1,5 +1,5 @@
 <phpunit
-	bootstrap="dev-lib/phpunit-plugin-bootstrap.php"
+	bootstrap="vendor/xwp/wp-dev-lib/phpunit-plugin-bootstrap.php"
 	backupGlobals="false"
 	colors="true"
 	convertErrorsToExceptions="true"
@@ -21,7 +21,6 @@
 		<whitelist processUncoveredFilesFromWhitelist="false">
 			<directory suffix=".php">./</directory>
 			<exclude>
-				<directory suffix=".php">dev-lib</directory>
 				<directory suffix=".php">svn</directory>
 				<directory suffix=".php">node_modules</directory>
 				<directory suffix=".php">tests</directory>

From 599181c0d11376c41d3ac7fc812bee08b896f4b3 Mon Sep 17 00:00:00 2001
From: Marcelo Vani <marcellovani@yahoo.co.uk>
Date: Thu, 29 Nov 2018 14:46:06 +0000
Subject: [PATCH 04/17] Fixing scripts

---
 bin/amphtml-update.sh             | 6 +++---
 bin/create-gutenberg-test-post.sh | 2 +-
 bin/install-wp-tests.sh           | 3 ++-
 3 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/bin/amphtml-update.sh b/bin/amphtml-update.sh
index 653ceed52ba..89f6a96c09a 100644
--- a/bin/amphtml-update.sh
+++ b/bin/amphtml-update.sh
@@ -17,14 +17,14 @@ fi
 sudo apt-get install git python protobuf-compiler python-protobuf
 
 # Create and go to vendor.
-if [[ ! -e $VENDOR_PATH ]]; then
+if [ ! -e $VENDOR_PATH ]; then
 	mkdir $VENDOR_PATH
 fi
 cd $VENDOR_PATH
 
 # Clone amphtml repo.
-if [[ ! -e $VENDOR_PATH/amphtml ]]; then
-	git clone https://github.com/ampproject/amphtml amphtml
+if [ ! -e $VENDOR_PATH/amphtml ]; then
+	git clone --depth=1 https://github.com/ampproject/amphtml amphtml
 else
 	cd $VENDOR_PATH/amphtml/validator
 	git fetch --tags
diff --git a/bin/create-gutenberg-test-post.sh b/bin/create-gutenberg-test-post.sh
index 1c719dac00c..a2513887110 100644
--- a/bin/create-gutenberg-test-post.sh
+++ b/bin/create-gutenberg-test-post.sh
@@ -13,7 +13,7 @@ if [[ ! -e $GUTENBERG_PATH ]]; then
 	echo "This needs to clone the Gutenberg plugin into your plugins directory, as it looks like it's not there."
 	read -p "Is that alright? y/n " -r
 	if [[ $REPLY =~ [Yy] ]]; then
-		git clone https://github.com/WordPress/gutenberg.git
+		git clone --depth=1 https://github.com/WordPress/gutenberg.git
 		wp plugin activate gutenberg
 		echo "The Gutenberg plugin is cloned. Please follow the build steps:"
 		echo "https://github.com/WordPress/gutenberg/blob/master/CONTRIBUTING.md"
diff --git a/bin/install-wp-tests.sh b/bin/install-wp-tests.sh
index 9f009876bfb..1a6c88a5a0a 100755
--- a/bin/install-wp-tests.sh
+++ b/bin/install-wp-tests.sh
@@ -104,7 +104,8 @@ install_db() {
 	fi
 
 	# create database
-	mysqladmin create $DB_NAME --user="$DB_USER" --password="$DB_PASS"$EXTRA
+	mysql --user="$DB_USER" --password="$DB_PASS"$EXTRA -e"DROP DATABASE IF EXISTS $DB_NAME"
+	mysql --user="$DB_USER" --password="$DB_PASS"$EXTRA -e"create DATABASE $DB_NAME"
 }
 
 install_wp

From 807b48fe3619af0357965c110c5fe711f24a9bd2 Mon Sep 17 00:00:00 2001
From: Marcelo Vani <marcellovani@yahoo.co.uk>
Date: Thu, 29 Nov 2018 14:57:35 +0000
Subject: [PATCH 05/17] Speeding up script

---
 bin/amphtml-update.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/bin/amphtml-update.sh b/bin/amphtml-update.sh
index 89f6a96c09a..c83ad4e05ad 100644
--- a/bin/amphtml-update.sh
+++ b/bin/amphtml-update.sh
@@ -26,8 +26,8 @@ cd $VENDOR_PATH
 if [ ! -e $VENDOR_PATH/amphtml ]; then
 	git clone --depth=1 https://github.com/ampproject/amphtml amphtml
 else
-	cd $VENDOR_PATH/amphtml/validator
-	git fetch --tags
+	cd $VENDOR_PATH/amphtml
+	git pull
 fi
 
 # Check out the latest tag.

From 60615fff192ca0495ab93b7ebfd7a261c09f5458 Mon Sep 17 00:00:00 2001
From: Marcelo Vani <marcellovani@yahoo.co.uk>
Date: Thu, 29 Nov 2018 14:57:44 +0000
Subject: [PATCH 06/17] Run update

---
 .../class-amp-allowed-tags-generated.php      | 428 ++++++++++++++----
 1 file changed, 346 insertions(+), 82 deletions(-)

diff --git a/includes/sanitizers/class-amp-allowed-tags-generated.php b/includes/sanitizers/class-amp-allowed-tags-generated.php
index 7d85042a281..f25c2ac88a0 100644
--- a/includes/sanitizers/class-amp-allowed-tags-generated.php
+++ b/includes/sanitizers/class-amp-allowed-tags-generated.php
@@ -13,7 +13,7 @@
  */
 class AMP_Allowed_Tags_Generated {
 
-	private static $spec_file_revision = 757;
+	private static $spec_file_revision = 772;
 	private static $minimum_validator_revision_required = 348;
 
 	private static $allowed_tags = array(
@@ -1680,6 +1680,36 @@ class AMP_Allowed_Tags_Generated {
 				),
 			),
 		),
+		'amp-delight-player' => array(
+			array(
+				'attr_spec_list' => array(
+					'data-content-id' => array(
+						'mandatory' => true,
+					),
+					'media' => array(),
+					'noloading' => array(
+						'value' => array(
+							'',
+						),
+					),
+				),
+				'tag_spec' => array(
+					'amp_layout' => array(
+						'supported_layouts' => array(
+							6,
+							2,
+							3,
+							7,
+							1,
+							4,
+						),
+					),
+					'requires_extension' => array(
+						'amp-delight-player',
+					),
+				),
+			),
+		),
 		'amp-embed' => array(
 			array(
 				'attr_spec_list' => array(
@@ -2936,6 +2966,36 @@ class AMP_Allowed_Tags_Generated {
 					'unique' => true,
 				),
 			),
+			array(
+				'attr_spec_list' => array(
+					'data-client' => array(
+						'mandatory' => true,
+					),
+					'data-slot' => array(
+						'mandatory' => true,
+					),
+					'type' => array(
+						'mandatory' => true,
+						'value' => array(
+							'adsense',
+						),
+					),
+				),
+				'tag_spec' => array(
+					'reference_points' => array(
+						'AMP-NEXT-PAGE > [separator]' => array(
+							'mandatory' => false,
+							'unique' => true,
+						),
+					),
+					'requires_extension' => array(
+						'amp-next-page',
+					),
+					'spec_name' => 'amp-next-page [type=adsense]',
+					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-next-page',
+					'unique' => true,
+				),
+			),
 		),
 		'amp-nexxtv-player' => array(
 			array(
@@ -3438,47 +3498,6 @@ class AMP_Allowed_Tags_Generated {
 				),
 			),
 		),
-		'amp-script' => array(
-			array(
-				'attr_spec_list' => array(
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							5,
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'disallowed_ancestor' => array(
-						'amp-script',
-					),
-					'requires_extension' => array(
-						'amp-script',
-					),
-				),
-			),
-		),
 		'amp-selector' => array(
 			array(
 				'attr_spec_list' => array(
@@ -4376,6 +4395,151 @@ class AMP_Allowed_Tags_Generated {
 				),
 			),
 		),
+		'amp-video-iframe' => array(
+			array(
+				'attr_spec_list' => array(
+					'album' => array(),
+					'alt' => array(),
+					'artist' => array(),
+					'artwork' => array(),
+					'attribution' => array(),
+					'autoplay' => array(
+						'value' => array(
+							'',
+						),
+					),
+					'implements-media-session' => array(
+						'value' => array(
+							'',
+						),
+					),
+					'implements-rotate-to-fullscreen' => array(
+						'value' => array(
+							'',
+						),
+					),
+					'lightbox' => array(),
+					'lightbox-thumbnail-id' => array(
+						'value_regex_casei' => '^[a-z][a-z\\d_-]*',
+					),
+					'media' => array(),
+					'noloading' => array(
+						'value' => array(
+							'',
+						),
+					),
+					'poster' => array(
+						'mandatory' => true,
+					),
+					'referrerpolicy' => array(),
+					'rotate-to-fullscreen' => array(
+						'value' => array(
+							'',
+						),
+					),
+					'src' => array(
+						'blacklisted_value_regex' => '__amp_source_origin',
+						'mandatory' => true,
+						'value_url' => array(
+							'protocol' => array(
+								'https',
+							),
+						),
+					),
+				),
+				'tag_spec' => array(
+					'amp_layout' => array(
+						'supported_layouts' => array(
+							6,
+							2,
+							3,
+							7,
+							9,
+							1,
+							4,
+						),
+					),
+					'requires_extension' => array(
+						'amp-video-iframe',
+					),
+					'spec_name' => 'AMP-VIDEO-IFRAME[poster]',
+					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-video-iframe',
+				),
+			),
+			array(
+				'attr_spec_list' => array(
+					'album' => array(),
+					'alt' => array(),
+					'artist' => array(),
+					'artwork' => array(),
+					'attribution' => array(),
+					'autoplay' => array(
+						'value' => array(
+							'',
+						),
+					),
+					'implements-media-session' => array(
+						'value' => array(
+							'',
+						),
+					),
+					'implements-rotate-to-fullscreen' => array(
+						'value' => array(
+							'',
+						),
+					),
+					'lightbox' => array(),
+					'lightbox-thumbnail-id' => array(
+						'value_regex_casei' => '^[a-z][a-z\\d_-]*',
+					),
+					'media' => array(),
+					'noloading' => array(
+						'value' => array(
+							'',
+						),
+					),
+					'referrerpolicy' => array(),
+					'rotate-to-fullscreen' => array(
+						'value' => array(
+							'',
+						),
+					),
+					'src' => array(
+						'blacklisted_value_regex' => '__amp_source_origin',
+						'mandatory' => true,
+						'value_url' => array(
+							'protocol' => array(
+								'https',
+							),
+						),
+					),
+				),
+				'tag_spec' => array(
+					'amp_layout' => array(
+						'supported_layouts' => array(
+							6,
+							2,
+							3,
+							7,
+							9,
+							1,
+							4,
+						),
+					),
+					'reference_points' => array(
+						'AMP-VIDEO-IFRAME > [placeholder]' => array(
+							'mandatory' => true,
+							'unique' => true,
+						),
+					),
+					'requires_extension' => array(
+						'amp-video-iframe',
+					),
+					'spec_name' => 'AMP-VIDEO-IFRAME with [placeholder]',
+					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-video-iframe',
+				),
+			),
+		),
 		'amp-vimeo' => array(
 			array(
 				'attr_spec_list' => array(
@@ -6807,6 +6971,7 @@ class AMP_Allowed_Tags_Generated {
 			array(
 				'attr_spec_list' => array(
 					'alt' => array(),
+					'attribution' => array(),
 					'border' => array(),
 					'decoding' => array(
 						'value' => array(
@@ -6826,6 +6991,7 @@ class AMP_Allowed_Tags_Generated {
 							),
 						),
 					),
+					'sizes' => array(),
 					'src' => array(
 						'alternative_names' => array(
 							'srcset',
@@ -10025,6 +10191,31 @@ class AMP_Allowed_Tags_Generated {
 					),
 				),
 			),
+			array(
+				'attr_spec_list' => array(
+					'async' => array(
+						'mandatory' => true,
+						'value' => array(
+							'',
+						),
+					),
+					'nonce' => array(),
+					'type' => array(
+						'value_casei' => array(
+							'text/javascript',
+						),
+					),
+				),
+				'tag_spec' => array(
+					'extension_spec' => array(
+						'name' => 'amp-delight-player',
+						'version' => array(
+							'0.1',
+							'latest',
+						),
+					),
+				),
+			),
 			array(
 				'attr_spec_list' => array(
 					'async' => array(
@@ -11346,31 +11537,6 @@ class AMP_Allowed_Tags_Generated {
 					),
 				),
 			),
-			array(
-				'attr_spec_list' => array(
-					'async' => array(
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'nonce' => array(),
-					'type' => array(
-						'value_casei' => array(
-							'text/javascript',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'extension_spec' => array(
-						'name' => 'amp-script',
-						'version' => array(
-							'0.1',
-							'latest',
-						),
-					),
-				),
-			),
 			array(
 				'attr_spec_list' => array(
 					'async' => array(
@@ -11637,6 +11803,25 @@ class AMP_Allowed_Tags_Generated {
 					),
 				),
 			),
+			array(
+				'attr_spec_list' => array(
+					'type' => array(
+						'dispatch_key' => 3,
+						'mandatory' => true,
+						'value_casei' => array(
+							'application/json',
+						),
+					),
+				),
+				'tag_spec' => array(
+					'mandatory_parent' => 'amp-story-bookend',
+					'requires_extension' => array(
+						'amp-story',
+					),
+					'spec_name' => 'amp-story-bookend extension .json script',
+					'unique' => true,
+				),
+			),
 			array(
 				'attr_spec_list' => array(
 					'nonce' => array(),
@@ -11830,6 +12015,61 @@ class AMP_Allowed_Tags_Generated {
 					),
 				),
 			),
+			array(
+				'attr_spec_list' => array(
+					'async' => array(
+						'mandatory' => true,
+						'value' => array(
+							'',
+						),
+					),
+					'nonce' => array(),
+					'type' => array(
+						'value_casei' => array(
+							'text/javascript',
+						),
+					),
+				),
+				'tag_spec' => array(
+					'extension_spec' => array(
+						'name' => 'amp-video-docking',
+						'requires_usage' => 3,
+						'version' => array(
+							'0.1',
+							'latest',
+						),
+					),
+					'requires_extension' => array(
+						'amp-video',
+					),
+					'spec_name' => 'amp-video-docking for amp-video',
+				),
+			),
+			array(
+				'attr_spec_list' => array(
+					'async' => array(
+						'mandatory' => true,
+						'value' => array(
+							'',
+						),
+					),
+					'nonce' => array(),
+					'type' => array(
+						'value_casei' => array(
+							'text/javascript',
+						),
+					),
+				),
+				'tag_spec' => array(
+					'extension_spec' => array(
+						'name' => 'amp-video-iframe',
+						'version' => array(
+							'0.1',
+							'latest',
+						),
+					),
+				),
+			),
 			array(
 				'attr_spec_list' => array(
 					'async' => array(
@@ -12463,21 +12703,6 @@ class AMP_Allowed_Tags_Generated {
 					'unique' => true,
 				),
 			),
-			array(
-				'attr_spec_list' => array(
-					'nonce' => array(),
-				),
-				'cdata' => array(
-					'cdata_regex' => 'body ?{opacity: ?0}',
-				),
-				'tag_spec' => array(
-					'mandatory_alternatives' => 'head > style[amp-boilerplate]',
-					'mandatory_parent' => 'head',
-					'spec_name' => 'head > style[amp-boilerplate] - old variant',
-					'spec_url' => 'https://github.com/ampproject/amphtml/blob/master/spec/amp-boilerplate.md',
-					'unique' => true,
-				),
-			),
 			array(
 				'attr_spec_list' => array(
 					'amp-boilerplate' => array(
@@ -14384,6 +14609,20 @@ class AMP_Allowed_Tags_Generated {
 				'animate-in-after' => array(),
 				'animate-in-delay' => array(),
 				'animate-in-duration' => array(),
+				'data-tooltip-icon' => array(
+					'value_url' => array(
+						'protocol' => array(
+							'http',
+							'https',
+							'data',
+						),
+					),
+				),
+				'target' => array(
+					'value' => array(
+						'_blank',
+					),
+				),
 			),
 			'tag_spec' => array(
 				'reference_points' => array(
@@ -14450,6 +14689,15 @@ class AMP_Allowed_Tags_Generated {
 				'animate-in-after' => array(),
 				'animate-in-delay' => array(),
 				'animate-in-duration' => array(),
+				'data-tooltip-icon' => array(
+					'value_url' => array(
+						'protocol' => array(
+							'http',
+							'https',
+							'data',
+						),
+					),
+				),
 				'grid-area' => array(),
 				'justify-content' => array(
 					'value' => array(
@@ -14478,6 +14726,11 @@ class AMP_Allowed_Tags_Generated {
 						'stretch',
 					),
 				),
+				'target' => array(
+					'value' => array(
+						'_blank',
+					),
+				),
 			),
 			'tag_spec' => array(
 				'reference_points' => array(
@@ -14490,6 +14743,17 @@ class AMP_Allowed_Tags_Generated {
 				'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-story',
 			),
 		),
+		'AMP-VIDEO-IFRAME > [placeholder]' => array(
+			'attr_spec_list' => array(
+				'placeholder' => array(
+					'mandatory' => true,
+				),
+			),
+			'tag_spec' => array(
+				'spec_name' => 'AMP-VIDEO-IFRAME > [placeholder]',
+				'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-video-iframe',
+			),
+		),
 	);
 
 

From e79d8f21bdc61ea0d868ae116a7153e5a1034984 Mon Sep 17 00:00:00 2001
From: Marcelo Vani <marcellovani@yahoo.co.uk>
Date: Thu, 29 Nov 2018 15:42:16 +0000
Subject: [PATCH 07/17] Moved files into amp-sanitizer library

---
 bin/amphtml-update.py                         |   648 -
 bin/amphtml-update.sh                         |    47 -
 composer.json                                 |     3 +-
 composer.lock                                 |    42 +-
 .../class-amp-allowed-tags-generated.php      | 14820 ----------------
 .../sanitizers/class-amp-audio-sanitizer.php  |   172 -
 .../sanitizers/class-amp-base-sanitizer.php   |   583 -
 .../class-amp-blacklist-sanitizer.php         |   301 -
 .../sanitizers/class-amp-block-sanitizer.php  |   133 -
 .../class-amp-comments-sanitizer.php          |   156 -
 .../class-amp-core-theme-sanitizer.php        |  1107 --
 .../sanitizers/class-amp-embed-sanitizer.php  |    47 -
 .../sanitizers/class-amp-form-sanitizer.php   |   156 -
 .../class-amp-gallery-block-sanitizer.php     |   207 -
 .../sanitizers/class-amp-iframe-sanitizer.php |   196 -
 .../sanitizers/class-amp-img-sanitizer.php    |   376 -
 .../class-amp-o2-player-sanitizer.php         |   140 -
 .../class-amp-playbuzz-sanitizer.php          |   146 -
 includes/sanitizers/class-amp-rule-spec.php   |   139 -
 .../sanitizers/class-amp-script-sanitizer.php |    49 -
 .../sanitizers/class-amp-style-sanitizer.php  |  2225 ---
 .../class-amp-tag-and-attribute-sanitizer.php |  1874 --
 .../sanitizers/class-amp-video-sanitizer.php  |   231 -
 23 files changed, 42 insertions(+), 23756 deletions(-)
 delete mode 100644 bin/amphtml-update.py
 delete mode 100644 bin/amphtml-update.sh
 delete mode 100644 includes/sanitizers/class-amp-allowed-tags-generated.php
 delete mode 100644 includes/sanitizers/class-amp-audio-sanitizer.php
 delete mode 100644 includes/sanitizers/class-amp-base-sanitizer.php
 delete mode 100644 includes/sanitizers/class-amp-blacklist-sanitizer.php
 delete mode 100644 includes/sanitizers/class-amp-block-sanitizer.php
 delete mode 100644 includes/sanitizers/class-amp-comments-sanitizer.php
 delete mode 100644 includes/sanitizers/class-amp-core-theme-sanitizer.php
 delete mode 100644 includes/sanitizers/class-amp-embed-sanitizer.php
 delete mode 100644 includes/sanitizers/class-amp-form-sanitizer.php
 delete mode 100644 includes/sanitizers/class-amp-gallery-block-sanitizer.php
 delete mode 100644 includes/sanitizers/class-amp-iframe-sanitizer.php
 delete mode 100644 includes/sanitizers/class-amp-img-sanitizer.php
 delete mode 100644 includes/sanitizers/class-amp-o2-player-sanitizer.php
 delete mode 100644 includes/sanitizers/class-amp-playbuzz-sanitizer.php
 delete mode 100644 includes/sanitizers/class-amp-rule-spec.php
 delete mode 100644 includes/sanitizers/class-amp-script-sanitizer.php
 delete mode 100644 includes/sanitizers/class-amp-style-sanitizer.php
 delete mode 100644 includes/sanitizers/class-amp-tag-and-attribute-sanitizer.php
 delete mode 100644 includes/sanitizers/class-amp-video-sanitizer.php

diff --git a/bin/amphtml-update.py b/bin/amphtml-update.py
deleted file mode 100644
index bf6071200c4..00000000000
--- a/bin/amphtml-update.py
+++ /dev/null
@@ -1,648 +0,0 @@
-"""
-This script is used to generate the 'class-amp-allowed-tags-generated.php'
-file that is used by the class AMP_Tag_And_Attribute_Sanitizer.
-
-A bash script, amphtml-update.sh, is provided to automatically run this script.  To run the bash script, type:
-
-`bash amphtml-update.sh`
-
-from within a Linux environment such as VVV.
-
-See the Updating Allowed Tags and Attributes section of the Contributing guide
-https://github.com/Automattic/amp-wp/blob/develop/contributing.md#updating-allowed-tags-and-attributes.
-
-Then have fun sanitizing your AMP posts!
-"""
-
-import glob
-import logging
-import os
-import platform
-import re
-import shutil
-import subprocess
-import sys
-import tempfile
-import collections
-import json
-import google
-
-def Die(msg):
-		print >> sys.stderr, msg
-		sys.exit(1)
-
-
-def SetupOutDir(out_dir):
-	"""Sets up a clean output directory.
-
-	Args:
-		out_dir: directory name of the output directory. Must not have slashes,
-			dots, etc.
-	"""
-	logging.info('entering ...')
-	assert re.match(r'^[a-zA-Z_\-0-9]+$', out_dir), 'bad out_dir: %s' % out_dir
-
-	if os.path.exists(out_dir):
-		subprocess.check_call(['rm', '-rf', out_dir])
-	os.mkdir(out_dir)
-	logging.info('... done')
-
-
-def GenValidatorPb2Py(out_dir):
-	"""Calls the proto compiler to generate validator_pb2.py.
-
-	Args:
-		out_dir: directory name of the output directory. Must not have slashes,
-			dots, etc.
-	"""
-	logging.info('entering ...')
-	assert re.match(r'^[a-zA-Z_\-0-9]+$', out_dir), 'bad out_dir: %s' % out_dir
-
-	subprocess.check_call(['protoc', 'validator.proto',
-												 '--python_out=%s' % out_dir])
-	open('%s/__init__.py' % out_dir, 'w').close()
-	logging.info('... done')
-
-
-def GenValidatorProtoascii(out_dir):
-	"""Assembles the validator protoascii file from the main and extensions.
-
-	Args:
-		out_dir: directory name of the output directory. Must not have slashes,
-			dots, etc.
-	"""
-	logging.info('entering ...')
-	assert re.match(r'^[a-zA-Z_\-0-9]+$', out_dir), 'bad out_dir: %s' % out_dir
-
-	protoascii_segments = [open('validator-main.protoascii').read()]
-	extensions = glob.glob('extensions/*/validator-*.protoascii')
-	# In the Github project, the extensions are located in a sibling directory
-	# to the validator rather than a child directory.
-	if not extensions:
-		extensions = glob.glob('../extensions/*/validator-*.protoascii')
-	extensions.sort()
-	for extension in extensions:
-		protoascii_segments.append(open(extension).read())
-	f = open('%s/validator.protoascii' % out_dir, 'w')
-	f.write(''.join(protoascii_segments))
-	f.close()
-
-	logging.info('... done')
-
-
-def GeneratePHP(out_dir):
-	"""Generates PHP for WordPress AMP plugin to consume.
-
-	Args:
-		out_dir: directory name of the output directory. Must not have slashes,
-			dots, etc.
-	"""
-	logging.info('entering ...')
-	assert re.match(r'^[a-zA-Z_\-0-9]+$', out_dir), 'bad out_dir: %s' % out_dir
-
-	allowed_tags, attr_lists, reference_points, versions = ParseRules(out_dir)
-
-	#Generate the output
-	out = []
-	GenerateHeaderPHP(out)
-	GenerateSpecVersionPHP(out, versions)
-	GenerateAllowedTagsPHP(out, allowed_tags)
-	GenerateLayoutAttributesPHP(out, attr_lists)
-	GenerateGlobalAttributesPHP(out, attr_lists)
-	GenerateReferencePointsPHP(out, reference_points)
-	GenerateFooterPHP(out)
-
-	# join out array into a single string and remove unneeded whitespace
-	output = re.sub("\\(\\s*\\)", "()", '\n'.join(out))
-
-	# replace 'True' with true and 'False' with false
-	output = re.sub("'True'", "true", output)
-	output = re.sub("'False'", "false", output)
-
-	# Write the php file to disk.
-	f = open('%s/class-amp-allowed-tags-generated.php' % out_dir, 'w')
-	# f.write('\n'.join(out))
-	f.write(output)
-	f.close()
-	logging.info('... done')
-
-
-def GenerateHeaderPHP(out):
-	logging.info('entering ...')
-
-	# Output the file's header
-	out.append('<?php')
-	out.append('/**')
-	out.append(' * Generated by %s - do not edit.' %
-						 os.path.basename(__file__))
-	out.append(' *')
-	out.append(' * This is a list of HTML tags and attributes that are allowed by the')
-	out.append(' * AMP specification. Note that tag names have been converted to lowercase.')
-	out.append(' *')
-	out.append(' * Note: This file only contains tags that are relevant to the `body` of')
-	out.append(' * an AMP page. To include additional elements modify the variable')
-	out.append(' * `mandatory_parent_blacklist` in the amp_wp_build.py script.')
-	out.append(' *')
-	out.append(' * phpcs:ignoreFile')
-	out.append(' */')
-	out.append('class AMP_Allowed_Tags_Generated {')
-	out.append('')
-	logging.info('... done')
-
-
-def GenerateSpecVersionPHP(out, versions):
-	logging.info('entering ...')
-
-	# Output the version of the spec file and matching validator version
-	if versions['spec_file_revision']:
-		out.append('\tprivate static $spec_file_revision = %d;' % versions['spec_file_revision'])
-	if versions['min_validator_revision_required']:
-		out.append('\tprivate static $minimum_validator_revision_required = %d;' % versions['min_validator_revision_required'])
-	logging.info('... done')
-
-
-def GenerateAllowedTagsPHP(out, allowed_tags):
-	logging.info('entering ...')
-
-  # Output the allowed tags dictionary along with each tag's allowed attributes
-	out.append('')
-	out.append('\tprivate static $allowed_tags = %s;' % Phpize( allowed_tags, 1 ).lstrip() )
-	logging.info('... done')
-
-
-def GenerateLayoutAttributesPHP(out, attr_lists):
-	logging.info('entering ...')
-
-	# Output the attribute list allowed for layouts.
-	out.append('')
-	out.append('\tprivate static $layout_allowed_attrs = %s;' % Phpize( attr_lists['$AMP_LAYOUT_ATTRS'], 1 ).lstrip() )
-	out.append('')
-	logging.info('... done')
-
-
-def GenerateGlobalAttributesPHP(out, attr_lists):
-	logging.info('entering ...')
-
-	# Output the globally allowed attribute list.
-	out.append('')
-	out.append('\tprivate static $globally_allowed_attrs = %s;' % Phpize( attr_lists['$GLOBAL_ATTRS'], 1 ).lstrip() )
-	out.append('')
-	logging.info('... done')
-
-def GenerateReferencePointsPHP(out, reference_points):
-	logging.info('entering ...')
-
-	# Output the reference points.
-	out.append('')
-	out.append('\tprivate static $reference_points = %s;' % Phpize( reference_points, 1 ).lstrip() )
-	out.append('')
-	logging.info('... done')
-
-def GenerateFooterPHP(out):
-	logging.info('entering ...')
-
-	# Output the footer.
-	out.append('''
-	/**
-	 * Get allowed tags.
-	 *
-	 * @since 0.5
-	 * @return array Allowed tags.
-	 */
-	public static function get_allowed_tags() {
-		return self::$allowed_tags;
-	}
-
-	/**
-	 * Get allowed tag.
-	 *
-	 * Get the rules for a single tag so that the entire data structure needn't be passed around.
-	 *
-	 * @since 0.7
-	 * @param string $node_name Tag name.
-	 * @return array|null Allowed tag, or null if the tag does not exist.
-	 */
-	public static function get_allowed_tag( $node_name ) {
-		if ( isset( self::$allowed_tags[ $node_name ] ) ) {
-			return self::$allowed_tags[ $node_name ];
-		}
-		return null;
-	}
-
-	/**
-	 * Get reference point spec.
-	 *
-	 * @since 1.0
-	 * @param string $tag_spec_name Tag spec name.
-	 * @return array|null Reference point spec, or null if does not exist.
-	 */
-	public static function get_reference_point_spec( $tag_spec_name ) {
-		if ( isset( self::$reference_points[ $tag_spec_name ] ) ) {
-			return self::$reference_points[ $tag_spec_name ];
-		}
-		return null;
-	}
-
-	/**
-	 * Get list of globally-allowed attributes.
-	 *
-	 * @since 0.5
-	 * @return array Allowed tag.
-	 */
-	public static function get_allowed_attributes() {
-		return self::$globally_allowed_attrs;
-	}
-
-	/**
-	 * Get layout attributes.
-	 *
-	 * @since 0.5
-	 * @return array Allowed tag.
-	 */
-	public static function get_layout_attributes() {
-		return self::$layout_allowed_attrs;
-	}''')
-
-	out.append('')
-
-	out.append('}')
-	out.append('')
-
-	logging.info('... done')
-
-
-def ParseRules(out_dir):
-	logging.info('entering ...')
-
-	# These imports happen late, within this method because they don't necessarily
-	# exist when the module starts running, and the ones that probably do
-	# are checked by CheckPrereqs.
-	from google.protobuf import text_format
-	from amp_wp import validator_pb2
-
-	allowed_tags = {}
-	attr_lists = {}
-	reference_points = {}
-	versions = {}
-
-	specfile='%s/validator.protoascii' % out_dir
-
-	validator_pb2=validator_pb2
-	text_format=text_format
-
-	# Merge specfile with message buffers.
-	rules = validator_pb2.ValidatorRules()
-	text_format.Merge(open(specfile).read(), rules)
-
-	# Record the version of this specfile and the corresponding validator version.
-	if rules.HasField('spec_file_revision'):
-		versions['spec_file_revision'] = rules.spec_file_revision
-
-	if rules.HasField('min_validator_revision_required'):
-		versions['min_validator_revision_required'] = rules.min_validator_revision_required
-
-	# Build a dictionary of the named attribute lists that are used by multiple tags.
-	for (field_desc, field_val) in rules.ListFields():
-		if 'attr_lists' == field_desc.name:
-			for attr_spec in field_val:
-				attr_lists[UnicodeEscape(attr_spec.name)] = GetAttrs(attr_spec.attrs)
-
-	# Build a dictionary of allowed tags and an associated list of their allowed
-	# attributes, values and other criteria.
-
-	# Don't include tags that have a mandatory parent with one of these tag names
-	# since we're only concerned with using this tag list to validate the HTML
-	# of the DOM
-	mandatory_parent_blacklist = [
-		'$ROOT',
-		'!DOCTYPE',
-	]
-
-	for (field_desc, field_val) in rules.ListFields():
-		if 'tags' == field_desc.name:
-			for tag_spec in field_val:
-
-				# Ignore tags that are outside of the body
-				if tag_spec.HasField('mandatory_parent') and tag_spec.mandatory_parent in mandatory_parent_blacklist and tag_spec.tag_name != 'HTML':
-					continue
-
-				# Ignore deprecated tags
-				if tag_spec.HasField('deprecation'):
-					continue
-
-				# Handle the special $REFERENCE_POINT tag
-				if '$REFERENCE_POINT' == tag_spec.tag_name:
-					reference_points[ tag_spec.spec_name ] = GetTagSpec(tag_spec, attr_lists)
-					continue
-
-				# If we made it here, then start adding the tag_spec
-				if tag_spec.tag_name.lower() not in allowed_tags:
-					tag_list = []
-				else:
-					tag_list = allowed_tags[UnicodeEscape(tag_spec.tag_name).lower()]
-				# AddTag(allowed_tags, tag_spec, attr_lists)
-
-				gotten_tag_spec = GetTagSpec(tag_spec, attr_lists)
-				if gotten_tag_spec is not None:
-					tag_list.append(gotten_tag_spec)
-					allowed_tags[UnicodeEscape(tag_spec.tag_name).lower()] = tag_list
-
-	logging.info('... done')
-	return allowed_tags, attr_lists, reference_points, versions
-
-
-def GetTagSpec(tag_spec, attr_lists):
-	logging.info('entering ...')
-
-	tag_dict = GetTagRules(tag_spec)
-	if tag_dict is None:
-		return None
-	attr_dict = GetAttrs(tag_spec.attrs)
-
-	# Now add attributes from any attribute lists to this tag.
-	for (tag_field_desc, tag_field_val) in tag_spec.ListFields():
-		if 'attr_lists' == tag_field_desc.name:
-			for attr_list in tag_field_val:
-				attr_dict.update(attr_lists[UnicodeEscape(attr_list)])
-
-	logging.info('... done')
-	tag_spec_dict = {'tag_spec':tag_dict, 'attr_spec_list':attr_dict}
-	if tag_spec.HasField('cdata'):
-		cdata_dict = {}
-		for (field_descriptor, field_value) in tag_spec.cdata.ListFields():
-			if isinstance(field_value, (unicode, str, bool, int)):
-				cdata_dict[ field_descriptor.name ] = field_value
-			elif hasattr( field_value, '_values' ):
-				cdata_dict[ field_descriptor.name ] = {}
-				for _value in field_value._values:
-					for (key,val) in _value.ListFields():
-						cdata_dict[ field_descriptor.name ][ key.name ] = val
-			elif 'css_spec' == field_descriptor.name:
-				css_spec = {}
-
-				css_spec['allowed_at_rules'] = []
-				for at_rule_spec in field_value.at_rule_spec:
-					if '$DEFAULT' == at_rule_spec.name:
-						continue
-					css_spec['allowed_at_rules'].append( at_rule_spec.name )
-
-				for css_spec_field_name in ( 'allowed_declarations', 'declaration', 'font_url_spec', 'image_url_spec', 'validate_keyframes' ):
-					if not hasattr( field_value, css_spec_field_name ):
-						continue
-					css_spec_field_value = getattr( field_value, css_spec_field_name )
-					if isinstance(css_spec_field_value, (list, collections.Sequence, google.protobuf.internal.containers.RepeatedScalarFieldContainer)):
-						css_spec[ css_spec_field_name ] = [ val for val in css_spec_field_value ]
-					elif hasattr( css_spec_field_value, 'ListFields' ):
-						css_spec[ css_spec_field_name ] = {}
-						for (css_spec_field_item_descriptor, css_spec_field_item_value) in getattr( field_value, css_spec_field_name ).ListFields():
-							if isinstance(css_spec_field_item_value, (list, collections.Sequence, google.protobuf.internal.containers.RepeatedScalarFieldContainer)):
-								css_spec[ css_spec_field_name ][ css_spec_field_item_descriptor.name ] = [ val for val in css_spec_field_item_value ]
-							else:
-								css_spec[ css_spec_field_name ][ css_spec_field_item_descriptor.name ] = css_spec_field_item_value
-					else:
-						css_spec[ css_spec_field_name ] = css_spec_field_value
-
-				cdata_dict['css_spec'] = css_spec
-		if len( cdata_dict ) > 0:
-			tag_spec_dict['cdata'] = cdata_dict
-
-	return tag_spec_dict
-
-
-def GetTagRules(tag_spec):
-	logging.info('entering ...')
-
-	tag_rules = {}
-
-	if hasattr(tag_spec, 'also_requires_tag') and tag_spec.also_requires_tag:
-		also_requires_tag_list = []
-		for also_requires_tag in tag_spec.also_requires_tag:
-			also_requires_tag_list.append(UnicodeEscape(also_requires_tag))
-		tag_rules['also_requires_tag'] = also_requires_tag_list
-
-	if hasattr(tag_spec, 'requires_extension') and len( tag_spec.requires_extension ) != 0:
-		requires_extension_list = []
-		for requires_extension in tag_spec.requires_extension:
-			requires_extension_list.append(requires_extension)
-		tag_rules['requires_extension'] = requires_extension_list
-
-	if hasattr(tag_spec, 'reference_points') and len( tag_spec.reference_points ) != 0:
-		tag_reference_points = {}
-		for reference_point_spec in tag_spec.reference_points:
-			tag_reference_points[ reference_point_spec.tag_spec_name ] = {
-				"mandatory": reference_point_spec.mandatory,
-				"unique": reference_point_spec.unique
-			}
-		if len( tag_reference_points ) > 0:
-			tag_rules['reference_points'] = tag_reference_points
-
-	if hasattr(tag_spec, 'also_requires_tag_warning') and len( tag_spec.also_requires_tag_warning ) != 0:
-		also_requires_tag_warning_list = []
-		for also_requires_tag_warning in tag_spec.also_requires_tag_warning:
-			also_requires_tag_warning_list.append(also_requires_tag_warning)
-		tag_rules['also_requires_tag_warning'] = also_requires_tag_warning_list
-
-	if tag_spec.disallowed_ancestor:
-		disallowed_ancestor_list = []
-		for disallowed_ancestor in tag_spec.disallowed_ancestor:
-			disallowed_ancestor_list.append(UnicodeEscape(disallowed_ancestor).lower())
-		tag_rules['disallowed_ancestor'] = disallowed_ancestor_list
-
-	if tag_spec.html_format:
-		html_format_list = []
-		has_amp_format = False
-		for html_format in tag_spec.html_format:
-			if 1 == html_format:
-				has_amp_format = True
-		if not has_amp_format:
-			return None
-
-	if tag_spec.HasField('extension_spec'):
-		extension_spec = {}
-		for field in tag_spec.extension_spec.ListFields():
-			if isinstance(field[1], (list, google.protobuf.internal.containers.RepeatedScalarFieldContainer)):
-				extension_spec[ field[0].name ] = []
-				for val in field[1]:
-					extension_spec[ field[0].name ].append( val )
-			else:
-				extension_spec[ field[0].name ] = field[1]
-		tag_rules['extension_spec'] = extension_spec
-
-	if tag_spec.HasField('mandatory'):
-		tag_rules['mandatory'] = tag_spec.mandatory
-
-	if tag_spec.HasField('mandatory_alternatives'):
-		tag_rules['mandatory_alternatives'] = UnicodeEscape(tag_spec.mandatory_alternatives)
-
-	if tag_spec.HasField('mandatory_ancestor'):
-		tag_rules['mandatory_ancestor'] = UnicodeEscape(tag_spec.mandatory_ancestor).lower()
-
-	if tag_spec.HasField('mandatory_ancestor_suggested_alternative'):
-		tag_rules['mandatory_ancestor_suggested_alternative'] = UnicodeEscape(tag_spec.mandatory_ancestor_suggested_alternative).lower()
-
-	if tag_spec.HasField('mandatory_parent'):
-		tag_rules['mandatory_parent'] = UnicodeEscape(tag_spec.mandatory_parent).lower()
-
-	if tag_spec.HasField('spec_name'):
-		tag_rules['spec_name'] = UnicodeEscape(tag_spec.spec_name)
-
-	if tag_spec.HasField('spec_url'):
-		tag_rules['spec_url'] = UnicodeEscape(tag_spec.spec_url)
-
-	if tag_spec.HasField('unique'):
-		tag_rules['unique'] = tag_spec.unique
-
-	if tag_spec.HasField('unique_warning'):
-		tag_rules['unique_warning'] = tag_spec.unique_warning
-
-	if tag_spec.HasField('amp_layout'):
-		amp_layout = {}
-		for field in tag_spec.amp_layout.ListFields():
-			if 'supported_layouts' == field[0].name:
-				amp_layout['supported_layouts'] = [ val for val in field[1] ]
-			else:
-				amp_layout[ field[0].name ] = field[1]
-		tag_rules['amp_layout'] = amp_layout
-
-	logging.info('... done')
-	return tag_rules
-
-
-def GetAttrs(attrs):
-	logging.info('entering ...')
-
-	attr_dict = {}
-	for attr_spec in attrs:
-
-		value_dict = GetValues(attr_spec)
-
-		# Add attribute name and alternative_names
-		attr_dict[UnicodeEscape(attr_spec.name)] = value_dict
-
-	logging.info('... done')
-	return attr_dict
-
-
-def GetValues(attr_spec):
-	logging.info('entering ...')
-
-	value_dict = {}
-
-	# Add alternative names
-	if attr_spec.alternative_names:
-		alt_names_list = []
-		for alternative_name in attr_spec.alternative_names:
-			alt_names_list.append(UnicodeEscape(alternative_name))
-		value_dict['alternative_names'] = alt_names_list
-
-	# Add blacklisted value regex
-	if attr_spec.HasField('blacklisted_value_regex'):
-		value_dict['blacklisted_value_regex'] = attr_spec.blacklisted_value_regex
-
-	# dispatch_key is an int
-	if attr_spec.HasField('dispatch_key'):
-		value_dict['dispatch_key'] = attr_spec.dispatch_key
-
-	# mandatory is a boolean
-	if attr_spec.HasField('mandatory'):
-		value_dict['mandatory'] = attr_spec.mandatory
-
-	# Add allowed value
-	if attr_spec.value:
-		value_dict['value'] = list( attr_spec.value )
-
-	# value_casei
-	if attr_spec.value_casei:
-		value_dict['value_casei'] = list( attr_spec.value_casei )
-
-	# value_regex
-	if attr_spec.HasField('value_regex'):
-		value_dict['value_regex'] = attr_spec.value_regex
-
-	# value_regex_casei
-	if attr_spec.HasField('value_regex_casei'):
-		value_dict['value_regex_casei'] = attr_spec.value_regex_casei
-
-	#value_properties is a dictionary of dictionaries
-	if attr_spec.HasField('value_properties'):
-		value_properties_dict = {}
-		for (value_properties_key, value_properties_val) in attr_spec.value_properties.ListFields():
-			for value_property in value_properties_val:
-				property_dict = {}
-				# print 'value_property.name: %s' % value_property.name
-				for (key,val) in value_property.ListFields():
-					if val != value_property.name:
-						if isinstance(val, unicode):
-							val = UnicodeEscape(val)
-						property_dict[UnicodeEscape(key.name)] = val
-				value_properties_dict[UnicodeEscape(value_property.name)] = property_dict
-		value_dict['value_properties'] = value_properties_dict
-
-	# value_url is a dictionary
-	if attr_spec.HasField('value_url'):
-		value_url_dict = {}
-		for (value_url_key, value_url_val) in attr_spec.value_url.ListFields():
-			if isinstance(value_url_val, (list, collections.Sequence, google.protobuf.internal.containers.RepeatedScalarFieldContainer)):
-				value_url_val_val = []
-				for val in value_url_val:
-					value_url_val_val.append(UnicodeEscape(val))
-			else:
-				value_url_val_val = value_url_val
-			value_url_dict[value_url_key.name] = value_url_val_val
-		value_dict['value_url'] = value_url_dict
-
-	logging.info('... done')
-	return value_dict
-
-
-def UnicodeEscape(string):
-	"""Helper function which escapes unicode characters.
-
-	Args:
-		string: A string which may contain unicode characters.
-	Returns:
-		An escaped string.
-	"""
-	return ('' + string).encode('unicode-escape')
-
-def Phpize(data, indent=0):
-	"""Helper function to convert JSON-serializable data into PHP literals.
-
-	Args:
-		data: Any JSON-serializable.
-	Returns:
-		String formatted as PHP literal.
-	"""
-	json_string = json.dumps(data, sort_keys=True, ensure_ascii=False)
-
-	pipe = subprocess.Popen(['php', '-r', 'var_export( json_decode( file_get_contents( "php://stdin" ), true ) );'], stdout=subprocess.PIPE, stdin=subprocess.PIPE, stderr=subprocess.STDOUT)
-	php_stdout = pipe.communicate(input=json_string)[0]
-	php_exported = php_stdout.decode()
-
-	# Clean up formatting.
-	# TODO: Just use PHPCBF for this.
-	php_exported = re.sub( r'^ +', lambda match: ( len(match.group(0))/2 ) * '\t', php_exported, flags=re.MULTILINE )
-	php_exported = php_exported.replace( 'array (', 'array(' )
-	php_exported = re.sub( r' => \n\s+', ' => ', php_exported, flags=re.MULTILINE )
-	php_exported = re.sub( r'^(\s+)\d+ =>\s*', r'\1', php_exported, flags=re.MULTILINE )
-
-	# Add additional indents.
-	if indent > 0:
-		php_exported = re.sub( r'^', '\t' * indent, php_exported, flags=re.MULTILINE )
-	return php_exported
-
-def Main():
-	"""The main method, which executes all build steps and runs the tests."""
-	logging.basicConfig(
-			format='[[%(filename)s %(funcName)s]] - %(message)s', level=logging.INFO)
-
-	out_dir = 'amp_wp'
-
-	SetupOutDir(out_dir)
-	GenValidatorProtoascii(out_dir)
-	GenValidatorPb2Py(out_dir)
-	GenValidatorProtoascii(out_dir)
-	GeneratePHP(out_dir)
-
-if __name__ == '__main__':
-	Main()
diff --git a/bin/amphtml-update.sh b/bin/amphtml-update.sh
deleted file mode 100644
index c83ad4e05ad..00000000000
--- a/bin/amphtml-update.sh
+++ /dev/null
@@ -1,47 +0,0 @@
-#!/bin/bash
-set -e
-
-# Go to the right location.
-cd "$(dirname "$0")"
-
-BIN_PATH="$(pwd)"
-PROJECT_PATH=$(dirname $PWD)
-VENDOR_PATH=$PROJECT_PATH/vendor
-
-if ! command -v apt-get >/dev/null 2>&1; then
-	echo "The AMP HTML uses apt-get, make sure to run this script in a Linux environment"
-	exit 1
-fi
-
-# Install dependencies.
-sudo apt-get install git python protobuf-compiler python-protobuf
-
-# Create and go to vendor.
-if [ ! -e $VENDOR_PATH ]; then
-	mkdir $VENDOR_PATH
-fi
-cd $VENDOR_PATH
-
-# Clone amphtml repo.
-if [ ! -e $VENDOR_PATH/amphtml ]; then
-	git clone --depth=1 https://github.com/ampproject/amphtml amphtml
-else
-	cd $VENDOR_PATH/amphtml
-	git pull
-fi
-
-# Check out the latest tag.
-cd $VENDOR_PATH/amphtml
-LATEST_TAG=$( git describe --abbrev=0 --tags )
-git checkout $LATEST_TAG
-
-# Copy script to location and go there.
-cp $BIN_PATH/amphtml-update.py $VENDOR_PATH/amphtml/validator
-cd $VENDOR_PATH/amphtml/validator
-
-# Run script.
-python amphtml-update.py
-mv amp_wp/class-amp-allowed-tags-generated.php ../../../includes/sanitizers/
-rm -r amp_wp
-
-echo "Generated from tag $LATEST_TAG"
diff --git a/composer.json b/composer.json
index ca15ebd0c16..e07f32fbca3 100644
--- a/composer.json
+++ b/composer.json
@@ -13,7 +13,8 @@
     "require": {
         "php": "^5.3.6 || ^7.0",
         "sabberworm/php-css-parser": "dev-master",
-        "xwp/wp-dev-lib": "dev-master"
+        "xwp/wp-dev-lib": "dev-master",
+        "marcelovani/amp-sanitizer": "dev-master"
     },
     "require-dev": {
         "wp-coding-standards/wpcs": "^0.14.0",
diff --git a/composer.lock b/composer.lock
index 83eed3b1af4..9731eaf8f8f 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,8 +4,45 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "712d01725ebb02474abc18782e3de7ac",
+    "content-hash": "aa0fbfa002263abe1019d76833748b0f",
     "packages": [
+        {
+            "name": "marcelovani/amp-sanitizer",
+            "version": "dev-master",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/marcelovani/amp-sanitizer.git",
+                "reference": "16b5d0d8695a708f3f27c0cd1a183bc8721e80ba"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/marcelovani/amp-sanitizer/zipball/16b5d0d8695a708f3f27c0cd1a183bc8721e80ba",
+                "reference": "16b5d0d8695a708f3f27c0cd1a183bc8721e80ba",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^5.3.6 || ^7.0"
+            },
+            "require-dev": {
+                "dealerdirect/phpcodesniffer-composer-installer": "^0.4.4",
+                "sabberworm/php-css-parser": "dev-master",
+                "wimg/php-compatibility": "^8.1",
+                "wp-coding-standards/wpcs": "^0.14.0"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "": "includes/sanitizers"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "GPL-2.0"
+            ],
+            "description": "Consumes AMPHtml rules and generates AMP sanitizers",
+            "homepage": "https://github.com/marcelovani/amp-sanitizer",
+            "time": "2018-11-29T15:33:45+00:00"
+        },
         {
             "name": "sabberworm/php-css-parser",
             "version": "dev-master",
@@ -309,7 +346,8 @@
     "minimum-stability": "stable",
     "stability-flags": {
         "sabberworm/php-css-parser": 20,
-        "xwp/wp-dev-lib": 20
+        "xwp/wp-dev-lib": 20,
+        "marcelovani/amp-sanitizer": 20
     },
     "prefer-stable": false,
     "prefer-lowest": false,
diff --git a/includes/sanitizers/class-amp-allowed-tags-generated.php b/includes/sanitizers/class-amp-allowed-tags-generated.php
deleted file mode 100644
index f25c2ac88a0..00000000000
--- a/includes/sanitizers/class-amp-allowed-tags-generated.php
+++ /dev/null
@@ -1,14820 +0,0 @@
-<?php
-/**
- * Generated by amphtml-update.py - do not edit.
- *
- * This is a list of HTML tags and attributes that are allowed by the
- * AMP specification. Note that tag names have been converted to lowercase.
- *
- * Note: This file only contains tags that are relevant to the `body` of
- * an AMP page. To include additional elements modify the variable
- * `mandatory_parent_blacklist` in the amp_wp_build.py script.
- *
- * phpcs:ignoreFile
- */
-class AMP_Allowed_Tags_Generated {
-
-	private static $spec_file_revision = 772;
-	private static $minimum_validator_revision_required = 348;
-
-	private static $allowed_tags = array(
-		'a' => array(
-			array(
-				'attr_spec_list' => array(
-					'[href]' => array(),
-					'border' => array(),
-					'download' => array(),
-					'href' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_empty' => true,
-							'protocol' => array(
-								'ftp',
-								'geo',
-								'http',
-								'https',
-								'mailto',
-								'maps',
-								'bip',
-								'bbmi',
-								'fb-messenger',
-								'intent',
-								'line',
-								'skype',
-								'sms',
-								'snapchat',
-								'tel',
-								'tg',
-								'threema',
-								'twitter',
-								'viber',
-								'webcal',
-								'web+mastodon',
-								'whatsapp',
-							),
-						),
-					),
-					'hreflang' => array(),
-					'media' => array(),
-					'name' => array(),
-					'referrerpolicy' => array(),
-					'rel' => array(
-						'blacklisted_value_regex' => '(^|\\s)(components|dns-prefetch|import|manifest|preconnect|prefetch|preload|prerender|serviceworker|stylesheet|subresource|)(\\s|$)',
-					),
-					'role' => array(),
-					'tabindex' => array(),
-					'target' => array(
-						'value' => array(
-							'_blank',
-							'_self',
-							'_top',
-						),
-					),
-					'type' => array(
-						'value_casei' => array(
-							'text/html',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#links',
-				),
-			),
-		),
-		'abbr' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'acronym' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'address' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'amp-3d-gltf' => array(
-			array(
-				'attr_spec_list' => array(
-					'alpha' => array(
-						'value' => array(
-							'false',
-							'true',
-						),
-					),
-					'antialiasing' => array(
-						'value' => array(
-							'false',
-							'true',
-						),
-					),
-					'autorotate' => array(
-						'value' => array(
-							'false',
-							'true',
-						),
-					),
-					'clearcolor' => array(),
-					'enablezoom' => array(
-						'value' => array(
-							'false',
-							'true',
-						),
-					),
-					'maxpixelratio' => array(
-						'value_regex' => '[+-]?(\\d*\\.)?\\d+',
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'src' => array(
-						'mandatory' => true,
-						'value_url' => array(
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-3d-gltf',
-					),
-				),
-			),
-		),
-		'amp-3q-player' => array(
-			array(
-				'attr_spec_list' => array(
-					'autoplay' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'data-id' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							7,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-3q-player',
-					),
-				),
-			),
-		),
-		'amp-accordion' => array(
-			array(
-				'attr_spec_list' => array(
-					'animate' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'disable-session-states' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'expand-single-section' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							5,
-						),
-					),
-					'requires_extension' => array(
-						'amp-accordion',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-accordion',
-				),
-			),
-		),
-		'amp-ad' => array(
-			array(
-				'attr_spec_list' => array(
-					'alt' => array(),
-					'json' => array(),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'rtc-config' => array(),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => true,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'template' => array(),
-					'type' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'also_requires_tag_warning' => array(
-						'amp-ad extension .js script',
-					),
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							8,
-							9,
-							1,
-							4,
-						),
-					),
-					'disallowed_ancestor' => array(
-						'amp-app-banner',
-					),
-					'requires_extension' => array(
-						'amp-ad',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-ad',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'alt' => array(),
-					'data-multi-size' => array(
-						'dispatch_key' => 2,
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'json' => array(),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'rtc-config' => array(),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => true,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'type' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'also_requires_tag_warning' => array(
-						'amp-ad extension .js script',
-					),
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							8,
-							9,
-							1,
-							4,
-						),
-					),
-					'disallowed_ancestor' => array(
-						'amp-app-banner',
-						'amp-carousel',
-						'amp-fx-flying-carpet',
-						'amp-lightbox',
-						'amp-sticky-ad',
-					),
-					'requires_extension' => array(
-						'amp-ad',
-					),
-					'spec_name' => 'amp-ad with data-multi-size attribute',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-ad',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'alt' => array(),
-					'data-enable-refresh' => array(
-						'dispatch_key' => 2,
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'json' => array(),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => true,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'type' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'also_requires_tag_warning' => array(
-						'amp-ad extension .js script',
-					),
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							8,
-							9,
-							1,
-							4,
-						),
-					),
-					'disallowed_ancestor' => array(
-						'amp-app-banner',
-						'amp-fx-flying-carpet',
-						'amp-lightbox',
-					),
-					'requires_extension' => array(
-						'amp-ad',
-					),
-					'spec_name' => 'amp-ad with data-enable-refresh attribute',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-ad',
-				),
-			),
-		),
-		'amp-addthis' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-pub-id' => array(
-						'mandatory' => true,
-					),
-					'data-share-media' => array(
-						'value_url' => array(
-							'allow_empty' => true,
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
-					'data-share-url' => array(
-						'value_url' => array(
-							'allow_empty' => true,
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
-					'data-widget-id' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-addthis',
-					),
-				),
-			),
-		),
-		'amp-analytics' => array(
-			array(
-				'attr_spec_list' => array(
-					'config' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_empty' => true,
-							'allow_relative' => true,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'type' => array(),
-				),
-				'tag_spec' => array(
-					'requires_extension' => array(
-						'amp-analytics',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-analytics',
-				),
-			),
-		),
-		'amp-anim' => array(
-			array(
-				'attr_spec_list' => array(
-					'alt' => array(),
-					'attribution' => array(),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'src' => array(
-						'alternative_names' => array(
-							'srcset',
-						),
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'protocol' => array(
-								'data',
-								'http',
-								'https',
-							),
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							9,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-anim',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-anim',
-				),
-			),
-		),
-		'amp-animation' => array(
-			array(
-				'attr_spec_list' => array(
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'trigger' => array(
-						'value' => array(
-							'visibility',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							1,
-						),
-					),
-					'requires_extension' => array(
-						'amp-animation',
-					),
-				),
-			),
-		),
-		'amp-apester-media' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-apester-channel-token' => array(
-						'value_regex' => '[0-9a-zA-Z]+',
-					),
-					'data-apester-media-id' => array(
-						'value_regex' => '[0-9a-zA-Z]+',
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-apester-media',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-apester-media',
-				),
-			),
-		),
-		'amp-app-banner' => array(
-			array(
-				'attr_spec_list' => array(
-					'id' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							1,
-						),
-					),
-					'mandatory_parent' => 'body',
-					'requires_extension' => array(
-						'amp-app-banner',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-app-banner',
-					'unique' => true,
-				),
-			),
-		),
-		'amp-audio' => array(
-			array(
-				'attr_spec_list' => array(
-					'album' => array(),
-					'artist' => array(),
-					'artwork' => array(),
-					'autoplay' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'controls' => array(),
-					'controlslist' => array(),
-					'loop' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'media' => array(),
-					'muted' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'preload' => array(
-						'value_casei' => array(
-							'auto',
-							'metadata',
-							'none',
-						),
-					),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => true,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'defines_default_height' => true,
-						'defines_default_width' => true,
-						'supported_layouts' => array(
-							2,
-							3,
-							1,
-						),
-					),
-					'disallowed_ancestor' => array(
-						'amp-story',
-					),
-					'requires_extension' => array(
-						'amp-audio',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-audio',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'album' => array(),
-					'artist' => array(),
-					'artwork' => array(),
-					'autoplay' => array(
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'controls' => array(),
-					'controlslist' => array(),
-					'loop' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'media' => array(),
-					'muted' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => true,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'defines_default_height' => true,
-						'defines_default_width' => true,
-						'supported_layouts' => array(
-							2,
-							3,
-							1,
-						),
-					),
-					'mandatory_ancestor' => 'amp-story',
-					'requires_extension' => array(
-						'amp-audio',
-					),
-					'spec_name' => 'amp-story >> amp-audio',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-audio',
-				),
-			),
-		),
-		'amp-auto-ads' => array(
-			array(
-				'attr_spec_list' => array(
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'type' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'disallowed_ancestor' => array(
-						'amp-auto-ads',
-					),
-					'requires_extension' => array(
-						'amp-auto-ads',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-auto-ads',
-				),
-			),
-		),
-		'amp-beopinion' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-account' => array(
-						'mandatory' => true,
-						'value_regex_casei' => '[0-9a-f]{24}',
-					),
-					'data-content' => array(
-						'value_regex_casei' => '[0-9a-f]{24}',
-					),
-					'data-my-content' => array(
-						'value' => array(
-							'0',
-							'1',
-						),
-					),
-					'data-name' => array(),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							9,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-beopinion',
-					),
-				),
-			),
-		),
-		'amp-bind-macro' => array(
-			array(
-				'attr_spec_list' => array(
-					'arguments' => array(),
-					'expression' => array(
-						'mandatory' => true,
-					),
-					'id' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'requires_extension' => array(
-						'amp-bind',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-bind',
-				),
-			),
-		),
-		'amp-bodymovin-animation' => array(
-			array(
-				'attr_spec_list' => array(
-					'loop' => array(
-						'value_casei' => array(
-							'false',
-							'number',
-							'true',
-						),
-					),
-					'noautoplay' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'renderer' => array(
-						'value_casei' => array(
-							'svg',
-							'html',
-						),
-					),
-					'src' => array(
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-bodymovin-animation',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-bodymovin-animation',
-				),
-			),
-		),
-		'amp-brid-player' => array(
-			array(
-				'attr_spec_list' => array(
-					'autoplay' => array(),
-					'data-outstream' => array(
-						'value_regex' => '[0-9]+',
-					),
-					'data-partner' => array(
-						'mandatory' => true,
-						'value_regex' => '[0-9]+',
-					),
-					'data-player' => array(
-						'mandatory' => true,
-						'value_regex' => '[0-9]+',
-					),
-					'data-playlist' => array(
-						'value_regex' => '[0-9]+',
-					),
-					'data-video' => array(
-						'value_regex' => '[0-9]+',
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-brid-player',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-brid-player',
-				),
-			),
-		),
-		'amp-brightcove' => array(
-			array(
-				'attr_spec_list' => array(
-					'[data-account]' => array(),
-					'[data-embed]' => array(),
-					'[data-player-id]' => array(),
-					'[data-player]' => array(),
-					'[data-playlist-id]' => array(),
-					'[data-referrer]' => array(),
-					'[data-video-id]' => array(),
-					'autoplay' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'data-account' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-brightcove',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-brightcove',
-				),
-			),
-		),
-		'amp-byside-content' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-label' => array(
-						'mandatory' => true,
-					),
-					'data-webcare-id' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-byside-content',
-					),
-				),
-			),
-		),
-		'amp-call-tracking' => array(
-			array(
-				'attr_spec_list' => array(
-					'config' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							5,
-							6,
-							2,
-							3,
-							7,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-call-tracking',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-call-tracking',
-				),
-			),
-		),
-		'amp-carousel' => array(
-			array(
-				'attr_spec_list' => array(
-					'[slide]' => array(),
-					'arrows' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'autoplay' => array(
-						'value_regex' => '(|[0-9]+)',
-					),
-					'controls' => array(),
-					'delay' => array(
-						'value_regex' => '[0-9]+',
-					),
-					'dots' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'loop' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'type' => array(
-						'value' => array(
-							'slides',
-							'carousel',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							9,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-carousel',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-carousel',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'[slide]' => array(),
-					'arrows' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'autoplay' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'controls' => array(),
-					'delay' => array(
-						'value_regex' => '[0-9]+',
-					),
-					'dots' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'lightbox' => array(
-						'mandatory' => true,
-					),
-					'loop' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'type' => array(
-						'value' => array(
-							'slides',
-							'carousel',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							9,
-							1,
-							4,
-						),
-					),
-					'reference_points' => array(
-						'AMP-CAROUSEL lightbox [child]' => array(
-							'mandatory' => false,
-							'unique' => false,
-						),
-						'AMP-CAROUSEL lightbox [lightbox-exclude]' => array(
-							'mandatory' => false,
-							'unique' => false,
-						),
-					),
-					'requires_extension' => array(
-						'amp-carousel',
-						'amp-lightbox-gallery',
-					),
-					'spec_name' => 'AMP-CAROUSEL [lightbox]',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-carousel',
-				),
-			),
-		),
-		'amp-consent' => array(
-			array(
-				'attr_spec_list' => array(
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							1,
-						),
-					),
-					'requires_extension' => array(
-						'amp-consent',
-					),
-					'unique' => true,
-				),
-			),
-		),
-		'amp-dailymotion' => array(
-			array(
-				'attr_spec_list' => array(
-					'autoplay' => array(),
-					'data-endscreen-enable' => array(
-						'value' => array(
-							'false',
-							'true',
-						),
-					),
-					'data-info' => array(
-						'value' => array(
-							'false',
-							'true',
-						),
-					),
-					'data-mute' => array(
-						'value' => array(
-							'false',
-							'true',
-						),
-					),
-					'data-sharing-enable' => array(
-						'value' => array(
-							'false',
-							'true',
-						),
-					),
-					'data-start' => array(
-						'value_regex' => '[0-9]+',
-					),
-					'data-ui-highlight' => array(
-						'value_regex_casei' => '([0-9a-f]{3}){1,2}',
-					),
-					'data-ui-logo' => array(
-						'value' => array(
-							'false',
-							'true',
-						),
-					),
-					'data-videoid' => array(
-						'mandatory' => true,
-						'value_regex_casei' => '[a-z0-9]+',
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-dailymotion',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-dailymotion',
-				),
-			),
-		),
-		'amp-date-countdown' => array(
-			array(
-				'attr_spec_list' => array(
-					'biggest-unit' => array(
-						'value_casei' => array(
-							'days',
-							'hours',
-							'minutes',
-							'seconds',
-						),
-					),
-					'end-date' => array(
-						'value_regex' => '\\d{4}-[01]\\d-[0-3]\\dT[0-2]\\d:[0-5]\\d(:[0-5]\\d(\\.\\d+)?)?(Z|[+-][0-1][0-9]:[0-5][0-9])',
-					),
-					'locale' => array(
-						'value_casei' => array(
-							'de',
-							'en',
-							'es',
-							'fr',
-							'id',
-							'it',
-							'ja',
-							'ko',
-							'nl',
-							'pt',
-							'ru',
-							'th',
-							'tr',
-							'vi',
-							'zh-cn',
-							'zh-tw',
-						),
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'offset-seconds' => array(
-						'value_regex' => '-?\\d+',
-					),
-					'template' => array(),
-					'timeleft-ms' => array(
-						'value_regex' => '\\d+',
-					),
-					'timestamp-ms' => array(
-						'value_regex' => '\\d{13}',
-					),
-					'timestamp-seconds' => array(
-						'value_regex' => '\\d{10}',
-					),
-					'when-ended' => array(
-						'value_casei' => array(
-							'continue',
-							'stop',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-date-countdown',
-					),
-				),
-			),
-		),
-		'amp-date-picker' => array(
-			array(
-				'attr_spec_list' => array(
-					'[max]' => array(),
-					'[min]' => array(),
-					'allow-blocked-ranges' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'blocked' => array(),
-					'date' => array(),
-					'day-size' => array(
-						'value_regex' => '[0-9]+',
-					),
-					'first-day-of-week' => array(
-						'value_regex' => '[0-6]',
-					),
-					'format' => array(),
-					'fullscreen' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'highlighted' => array(),
-					'input-selector' => array(),
-					'locale' => array(),
-					'max' => array(),
-					'media' => array(),
-					'min' => array(),
-					'mode' => array(
-						'value_casei' => array(
-							'static',
-						),
-					),
-					'month-format' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'number-of-months' => array(
-						'value_regex' => '[0-9]+',
-					),
-					'open-after-clear' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'open-after-select' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'type' => array(
-						'value_casei' => array(
-							'single',
-						),
-					),
-					'week-day-format' => array(),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							9,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-date-picker',
-					),
-					'spec_name' => 'amp-date-picker[type=single][mode=static]',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'[max]' => array(),
-					'[min]' => array(),
-					'allow-blocked-ranges' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'blocked' => array(),
-					'date' => array(),
-					'day-size' => array(
-						'value_regex' => '[0-9]+',
-					),
-					'first-day-of-week' => array(
-						'value_regex' => '[0-6]',
-					),
-					'format' => array(),
-					'highlighted' => array(),
-					'input-selector' => array(),
-					'locale' => array(),
-					'max' => array(),
-					'media' => array(),
-					'min' => array(),
-					'mode' => array(
-						'mandatory' => true,
-						'value_casei' => array(
-							'overlay',
-						),
-					),
-					'month-format' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'number-of-months' => array(
-						'value_regex' => '[0-9]+',
-					),
-					'open-after-clear' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'open-after-select' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'touch-keyboard-editable' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'type' => array(
-						'value_casei' => array(
-							'single',
-						),
-					),
-					'week-day-format' => array(),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							5,
-							1,
-						),
-					),
-					'requires_extension' => array(
-						'amp-date-picker',
-					),
-					'spec_name' => 'amp-date-picker[type=single][mode=overlay]',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'[max]' => array(),
-					'[min]' => array(),
-					'allow-blocked-ranges' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'blocked' => array(),
-					'day-size' => array(
-						'value_regex' => '[0-9]+',
-					),
-					'end-date' => array(),
-					'end-input-selector' => array(),
-					'first-day-of-week' => array(
-						'value_regex' => '[0-6]',
-					),
-					'format' => array(),
-					'fullscreen' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'highlighted' => array(),
-					'locale' => array(),
-					'max' => array(),
-					'media' => array(),
-					'min' => array(),
-					'minimum-nights' => array(
-						'value_regex' => '[0-9]+',
-					),
-					'mode' => array(
-						'value_casei' => array(
-							'static',
-						),
-					),
-					'month-format' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'number-of-months' => array(
-						'value_regex' => '[0-9]+',
-					),
-					'open-after-clear' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'open-after-select' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'start-date' => array(),
-					'start-input-selector' => array(),
-					'type' => array(
-						'mandatory' => true,
-						'value_casei' => array(
-							'range',
-						),
-					),
-					'week-day-format' => array(),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							9,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-date-picker',
-					),
-					'spec_name' => 'amp-date-picker[type=range][mode=static]',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'[max]' => array(),
-					'[min]' => array(),
-					'allow-blocked-ranges' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'blocked' => array(),
-					'day-size' => array(
-						'value_regex' => '[0-9]+',
-					),
-					'end-date' => array(),
-					'end-input-selector' => array(),
-					'first-day-of-week' => array(
-						'value_regex' => '[0-6]',
-					),
-					'format' => array(),
-					'highlighted' => array(),
-					'locale' => array(),
-					'max' => array(),
-					'media' => array(),
-					'min' => array(),
-					'minimum-nights' => array(
-						'value_regex' => '[0-9]+',
-					),
-					'mode' => array(
-						'mandatory' => true,
-						'value_casei' => array(
-							'overlay',
-						),
-					),
-					'month-format' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'number-of-months' => array(
-						'value_regex' => '[0-9]+',
-					),
-					'open-after-clear' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'open-after-select' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'start-date' => array(),
-					'start-input-selector' => array(),
-					'touch-keyboard-editable' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'type' => array(
-						'mandatory' => true,
-						'value_casei' => array(
-							'range',
-						),
-					),
-					'week-day-format' => array(),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							5,
-							1,
-						),
-					),
-					'requires_extension' => array(
-						'amp-date-picker',
-					),
-					'spec_name' => 'amp-date-picker[type=range][mode=overlay]',
-				),
-			),
-		),
-		'amp-delight-player' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-content-id' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-delight-player',
-					),
-				),
-			),
-		),
-		'amp-embed' => array(
-			array(
-				'attr_spec_list' => array(
-					'alt' => array(),
-					'json' => array(),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'rtc-config' => array(),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => true,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'template' => array(),
-					'type' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'also_requires_tag_warning' => array(
-						'amp-ad extension .js script',
-					),
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							8,
-							9,
-							1,
-							4,
-						),
-					),
-					'disallowed_ancestor' => array(
-						'amp-app-banner',
-					),
-					'requires_extension' => array(
-						'amp-ad',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-ad',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'alt' => array(),
-					'data-multi-size' => array(
-						'dispatch_key' => 2,
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'json' => array(),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'rtc-config' => array(),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => true,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'type' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'also_requires_tag_warning' => array(
-						'amp-ad extension .js script',
-					),
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							8,
-							9,
-							1,
-							4,
-						),
-					),
-					'disallowed_ancestor' => array(
-						'amp-app-banner',
-						'amp-carousel',
-						'amp-fx-flying-carpet',
-						'amp-lightbox',
-						'amp-sticky-ad',
-					),
-					'requires_extension' => array(
-						'amp-ad',
-					),
-					'spec_name' => 'amp-embed with data-multi-size attribute',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-ad',
-				),
-			),
-		),
-		'amp-embedly-card' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-url' => array(
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-embedly-card',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-embedly-card',
-				),
-			),
-		),
-		'amp-embedly-key' => array(
-			array(
-				'attr_spec_list' => array(
-					'value' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							1,
-						),
-					),
-					'requires_extension' => array(
-						'amp-embedly-card',
-					),
-					'unique' => true,
-				),
-			),
-		),
-		'amp-experiment' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(
-					'requires_extension' => array(
-						'amp-experiment',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-experiment',
-					'unique' => true,
-				),
-			),
-		),
-		'amp-facebook' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-href' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-facebook',
-					),
-				),
-			),
-		),
-		'amp-facebook-comments' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-href' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-facebook-comments',
-					),
-				),
-			),
-		),
-		'amp-facebook-like' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-href' => array(
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-facebook-like',
-					),
-				),
-			),
-		),
-		'amp-facebook-page' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-href' => array(
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-facebook-page',
-					),
-				),
-			),
-		),
-		'amp-fit-text' => array(
-			array(
-				'attr_spec_list' => array(
-					'max-font-size' => array(),
-					'media' => array(),
-					'min-font-size' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							9,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-fit-text',
-					),
-				),
-			),
-		),
-		'amp-font' => array(
-			array(
-				'attr_spec_list' => array(
-					'font-family' => array(
-						'mandatory' => true,
-					),
-					'font-style' => array(),
-					'font-variant' => array(),
-					'font-weight' => array(),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'on-error-add-class' => array(),
-					'on-error-remove-class' => array(),
-					'on-load-add-class' => array(),
-					'on-load-remove-class' => array(),
-					'timeout' => array(
-						'value_regex' => '[0-9]+',
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							1,
-						),
-					),
-					'requires_extension' => array(
-						'amp-font',
-					),
-				),
-			),
-		),
-		'amp-fx-flying-carpet' => array(
-			array(
-				'attr_spec_list' => array(
-					'height' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'requires_extension' => array(
-						'amp-fx-flying-carpet',
-					),
-				),
-			),
-		),
-		'amp-geo' => array(
-			array(
-				'attr_spec_list' => array(
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							1,
-						),
-					),
-					'requires_extension' => array(
-						'amp-geo',
-					),
-					'unique' => true,
-				),
-			),
-		),
-		'amp-gfycat' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-gfyid' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noautoplay' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-gfycat',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-gfycat',
-				),
-			),
-		),
-		'amp-gist' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-gistid' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							3,
-						),
-					),
-					'requires_extension' => array(
-						'amp-gist',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-gist',
-				),
-			),
-		),
-		'amp-google-document-embed' => array(
-			array(
-				'attr_spec_list' => array(
-					'[src]' => array(),
-					'[title]' => array(),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							9,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-google-document-embed',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-google-document-embed',
-				),
-			),
-		),
-		'amp-hulu' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-eid' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-hulu',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-hulu',
-				),
-			),
-		),
-		'amp-iframe' => array(
-			array(
-				'attr_spec_list' => array(
-					'[src]' => array(),
-					'allow' => array(),
-					'allowfullscreen' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'allowpaymentrequest' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'allowtransparency' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'frameborder' => array(
-						'value' => array(
-							'0',
-							'1',
-						),
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'referrerpolicy' => array(),
-					'resizable' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'sandbox' => array(),
-					'scrolling' => array(
-						'value' => array(
-							'auto',
-							'no',
-							'yes',
-						),
-					),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => true,
-							'protocol' => array(
-								'data',
-								'https',
-							),
-						),
-					),
-					'srcdoc' => array(),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							9,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-iframe',
-					),
-				),
-			),
-		),
-		'amp-ima-video' => array(
-			array(
-				'attr_spec_list' => array(
-					'autoplay' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'data-src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => true,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'data-tag' => array(
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => true,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'rotate-to-fullscreen' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-ima-video',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-ima-video',
-				),
-			),
-		),
-		'amp-image-lightbox' => array(
-			array(
-				'attr_spec_list' => array(
-					'controls' => array(),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							1,
-						),
-					),
-					'requires_extension' => array(
-						'amp-image-lightbox',
-					),
-				),
-			),
-		),
-		'amp-image-slider' => array(
-			array(
-				'attr_spec_list' => array(
-					'disable-hint-reappear' => array(),
-					'initial-slider-position' => array(
-						'value_regex' => '0(\\.[0-9]+)?|1(\\.0+)?',
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'step-size' => array(
-						'value_regex' => '0(\\.[0-9]+)?|1(\\.0+)?',
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							2,
-							9,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-image-slider',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-image-slider',
-				),
-			),
-		),
-		'amp-img' => array(
-			array(
-				'attr_spec_list' => array(
-					'[alt]' => array(),
-					'[attribution]' => array(),
-					'[src]' => array(),
-					'[srcset]' => array(),
-					'alt' => array(),
-					'attribution' => array(),
-					'lightbox' => array(),
-					'lightbox-thumbnail-id' => array(
-						'value_regex_casei' => '^[a-z][a-z\\d_-]*',
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'placeholder' => array(),
-					'src' => array(
-						'alternative_names' => array(
-							'srcset',
-						),
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'protocol' => array(
-								'data',
-								'http',
-								'https',
-							),
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							9,
-							1,
-							4,
-						),
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-img',
-				),
-			),
-		),
-		'amp-imgur' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-imgur-id' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-imgur',
-					),
-				),
-			),
-		),
-		'amp-instagram' => array(
-			array(
-				'attr_spec_list' => array(
-					'alt' => array(),
-					'data-shortcode' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-instagram',
-					),
-				),
-			),
-		),
-		'amp-install-serviceworker' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-iframe-src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => true,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => true,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							1,
-						),
-					),
-					'requires_extension' => array(
-						'amp-install-serviceworker',
-					),
-				),
-			),
-		),
-		'amp-izlesene' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-videoid' => array(
-						'mandatory' => true,
-						'value_regex' => '[0-9]+',
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-izlesene',
-					),
-				),
-			),
-		),
-		'amp-jwplayer' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-media-id' => array(
-						'value_regex_casei' => '[0-9a-z]{8}',
-					),
-					'data-player-id' => array(
-						'mandatory' => true,
-						'value_regex_casei' => '[0-9a-z]{8}',
-					),
-					'data-playlist-id' => array(
-						'value_regex_casei' => '[0-9a-z]{8}',
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-jwplayer',
-					),
-				),
-			),
-		),
-		'amp-kaltura-player' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-partner' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-kaltura-player',
-					),
-				),
-			),
-		),
-		'amp-layout' => array(
-			array(
-				'attr_spec_list' => array(
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							9,
-							1,
-							4,
-							5,
-						),
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-layout',
-				),
-			),
-		),
-		'amp-lightbox' => array(
-			array(
-				'attr_spec_list' => array(
-					'[open]' => array(),
-					'animate-in' => array(
-						'value_casei' => array(
-							'fade-in',
-							'fly-in-bottom',
-							'fly-in-top',
-						),
-					),
-					'controls' => array(),
-					'from' => array(),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'scrollable' => array(),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							1,
-						),
-					),
-					'requires_extension' => array(
-						'amp-lightbox',
-					),
-				),
-			),
-		),
-		'amp-list' => array(
-			array(
-				'attr_spec_list' => array(
-					'[src]' => array(),
-					'[state]' => array(),
-					'auto-resize' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'binding' => array(
-						'value' => array(
-							'always',
-							'no',
-							'refresh',
-						),
-					),
-					'credentials' => array(),
-					'items' => array(),
-					'max-items' => array(),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'reset-on-refresh' => array(
-						'value' => array(
-							'',
-							'always',
-							'fetch',
-						),
-					),
-					'single-item' => array(),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => true,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'template' => array(),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-list',
-					),
-				),
-			),
-		),
-		'amp-live-list' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-max-items-per-page' => array(
-						'mandatory' => true,
-						'value_regex' => '\\d+',
-					),
-					'data-poll-interval' => array(
-						'value_regex' => '\\d{5,}',
-					),
-					'disabled' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'id' => array(
-						'mandatory' => true,
-					),
-					'sort' => array(
-						'value' => array(
-							'ascending',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							5,
-							3,
-						),
-					),
-					'reference_points' => array(
-						'AMP-LIVE-LIST [items]' => array(
-							'mandatory' => true,
-							'unique' => true,
-						),
-						'AMP-LIVE-LIST [pagination]' => array(
-							'mandatory' => false,
-							'unique' => true,
-						),
-						'AMP-LIVE-LIST [update]' => array(
-							'mandatory' => true,
-							'unique' => true,
-						),
-					),
-					'requires_extension' => array(
-						'amp-live-list',
-					),
-				),
-			),
-		),
-		'amp-mathml' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-formula' => array(
-						'mandatory' => true,
-					),
-					'inline' => array(),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							5,
-						),
-					),
-					'requires_extension' => array(
-						'amp-mathml',
-					),
-				),
-			),
-		),
-		'amp-mowplayer' => array(
-			array(
-				'attr_spec_list' => array(
-					'autoplay' => array(),
-					'data-mediaid' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-mowplayer',
-					),
-				),
-			),
-		),
-		'amp-next-page' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(
-					'reference_points' => array(
-						'AMP-NEXT-PAGE > [separator]' => array(
-							'mandatory' => false,
-							'unique' => true,
-						),
-						'amp-next-page extension .json configuration' => array(
-							'mandatory' => true,
-							'unique' => true,
-						),
-					),
-					'requires_extension' => array(
-						'amp-next-page',
-					),
-					'spec_name' => 'amp-next-page with inline config',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-next-page',
-					'unique' => true,
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-				),
-				'tag_spec' => array(
-					'reference_points' => array(
-						'AMP-NEXT-PAGE > [separator]' => array(
-							'mandatory' => false,
-							'unique' => true,
-						),
-					),
-					'requires_extension' => array(
-						'amp-next-page',
-					),
-					'spec_name' => 'amp-next-page with src attribute',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-next-page',
-					'unique' => true,
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'data-client' => array(
-						'mandatory' => true,
-					),
-					'data-slot' => array(
-						'mandatory' => true,
-					),
-					'type' => array(
-						'mandatory' => true,
-						'value' => array(
-							'adsense',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'reference_points' => array(
-						'AMP-NEXT-PAGE > [separator]' => array(
-							'mandatory' => false,
-							'unique' => true,
-						),
-					),
-					'requires_extension' => array(
-						'amp-next-page',
-					),
-					'spec_name' => 'amp-next-page [type=adsense]',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-next-page',
-					'unique' => true,
-				),
-			),
-		),
-		'amp-nexxtv-player' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-client' => array(
-						'mandatory' => true,
-					),
-					'data-mediaid' => array(
-						'mandatory' => true,
-						'value_regex' => '[^=/?:]+',
-					),
-					'data-mode' => array(
-						'value' => array(
-							'api',
-							'static',
-						),
-					),
-					'data-origin' => array(
-						'value_url' => array(
-							'allow_empty' => true,
-							'protocol' => array(
-								'https',
-								'http',
-							),
-						),
-					),
-					'data-streamtype' => array(
-						'value' => array(
-							'album',
-							'audio',
-							'live',
-							'playlist',
-							'playlist-marked',
-							'video',
-						),
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-nexxtv-player',
-					),
-				),
-			),
-		),
-		'amp-o2-player' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-bcid' => array(
-						'mandatory' => true,
-					),
-					'data-pid' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-o2-player',
-					),
-				),
-			),
-		),
-		'amp-ooyala-player' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-embedcode' => array(
-						'mandatory' => true,
-					),
-					'data-pcode' => array(
-						'mandatory' => true,
-					),
-					'data-playerid' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							7,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-ooyala-player',
-					),
-				),
-			),
-		),
-		'amp-orientation-observer' => array(
-			array(
-				'attr_spec_list' => array(
-					'alpha-range' => array(
-						'value_regex' => '(\\d+)\\s{1}(\\d+)',
-					),
-					'beta-range' => array(
-						'value_regex' => '(\\d+)\\s{1}(\\d+)',
-					),
-					'gamma-range' => array(
-						'value_regex' => '(\\d+)\\s{1}(\\d+)',
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							1,
-						),
-					),
-					'requires_extension' => array(
-						'amp-orientation-observer',
-					),
-				),
-			),
-		),
-		'amp-pan-zoom' => array(
-			array(
-				'attr_spec_list' => array(
-					'disable-double-tap' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'initial-scale' => array(
-						'value_regex' => '[0-9]+(\\.[0-9]+)?',
-					),
-					'initial-x' => array(
-						'value_regex' => '[0-9]+',
-					),
-					'initial-y' => array(
-						'value_regex' => '[0-9]+',
-					),
-					'max-scale' => array(
-						'value_regex' => '[0-9]+(\\.[0-9]+)?',
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'reset-on-resize' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-pan-zoom',
-					),
-				),
-			),
-		),
-		'amp-pinterest' => array(
-			array(
-				'attr_spec_list' => array(
-					'alt' => array(),
-					'data-do' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-pinterest',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-pinterest',
-				),
-			),
-		),
-		'amp-pixel' => array(
-			array(
-				'attr_spec_list' => array(
-					'allow-ssr-img' => array(),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'referrerpolicy' => array(
-						'value' => array(
-							'no-referrer',
-						),
-					),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_empty' => true,
-							'allow_relative' => true,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'defines_default_height' => true,
-						'defines_default_width' => true,
-						'supported_layouts' => array(
-							2,
-							1,
-						),
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-pixel',
-				),
-			),
-		),
-		'amp-playbuzz' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-comments' => array(
-						'value_casei' => array(
-							'false',
-							'true',
-						),
-					),
-					'data-item' => array(),
-					'data-item-info' => array(
-						'value_casei' => array(
-							'false',
-							'true',
-						),
-					),
-					'data-share-buttons' => array(
-						'value_casei' => array(
-							'false',
-							'true',
-						),
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'src' => array(),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							4,
-							3,
-						),
-					),
-					'requires_extension' => array(
-						'amp-playbuzz',
-					),
-				),
-			),
-		),
-		'amp-position-observer' => array(
-			array(
-				'attr_spec_list' => array(
-					'intersection-ratios' => array(
-						'value_regex' => '^([0]*?\\.\\d*$|1$|0$)|([0]*?\\.\\d*|1|0)\\s{1}([0]*?\\.\\d*$|1$|0$)',
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'once' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'target' => array(),
-					'viewport-margins' => array(
-						'value_regex' => '^(\\d+$|\\d+px$|\\d+vh$)|((\\d+|\\d+px|\\d+vh)\\s{1}(\\d+$|\\d+px$|\\d+vh$))',
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							1,
-						),
-					),
-					'requires_extension' => array(
-						'amp-position-observer',
-					),
-				),
-			),
-		),
-		'amp-powr-player' => array(
-			array(
-				'attr_spec_list' => array(
-					'[data-referrer]' => array(),
-					'autoplay' => array(),
-					'data-account' => array(
-						'mandatory' => true,
-						'value_regex' => '[0-9a-zA-Z-]+',
-					),
-					'data-player' => array(
-						'mandatory' => true,
-						'value_regex' => '[0-9a-zA-Z-]+',
-					),
-					'data-terms' => array(),
-					'data-video' => array(
-						'value_regex' => '[0-9a-zA-Z-]+',
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-powr-player',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-powr-player',
-				),
-			),
-		),
-		'amp-reach-player' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-embed-id' => array(
-						'mandatory' => true,
-						'value_regex' => '[0-9a-z-]+',
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-reach-player',
-					),
-				),
-			),
-		),
-		'amp-reddit' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-embedlive' => array(
-						'value_casei' => array(
-							'false',
-							'true',
-						),
-					),
-					'data-embedparent' => array(
-						'value_casei' => array(
-							'false',
-							'true',
-						),
-					),
-					'data-embedtype' => array(
-						'mandatory' => true,
-						'value_casei' => array(
-							'comment',
-							'post',
-						),
-					),
-					'data-src' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-reddit',
-					),
-				),
-			),
-		),
-		'amp-riddle-quiz' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-riddle-id' => array(
-						'mandatory' => true,
-						'value_regex' => '[0-9]+',
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-riddle-quiz',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-riddle-quiz',
-				),
-			),
-		),
-		'amp-selector' => array(
-			array(
-				'attr_spec_list' => array(
-					'[disabled]' => array(),
-					'[selected]' => array(),
-					'disabled' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'form' => array(),
-					'keyboard-select-mode' => array(
-						'value_casei' => array(
-							'focus',
-							'none',
-							'select',
-						),
-					),
-					'media' => array(),
-					'multiple' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'name' => array(
-						'blacklisted_value_regex' => '(^|\\s)(__amp_\\S*|__count__|__defineGetter__|__defineSetter__|__lookupGetter__|__lookupSetter__|__noSuchMethod__|__parent__|__proto__|__AMP_\\S*|\\$p|\\$proxy|acceptCharset|addEventListener|appendChild|assignedSlot|attachShadow|baseURI|checkValidity|childElementCount|childNodes|classList|className|clientHeight|clientLeft|clientTop|clientWidth|compareDocumentPosition|computedName|computedRole|contentEditable|createShadowRoot|enqueAction|firstChild|firstElementChild|getAnimations|getAttribute|getAttributeNS|getAttributeNode|getAttributeNodeNS|getBoundingClientRect|getClientRects|getDestinationInsertionPoints|getElementsByClassName|getElementsByTagName|getElementsByTagNameNS|getRootNode|hasAttribute|hasAttributeNS|hasAttributes|hasChildNodes|hasPointerCapture|innerHTML|innerText|inputMode|insertAdjacentElement|insertAdjacentHTML|insertAdjacentText|isContentEditable|isDefaultNamespace|isEqualNode|isSameNode|lastChild|lastElementChild|lookupNamespaceURI|namespaceURI|nextElementSibling|nextSibling|nodeName|nodeType|nodeValue|offsetHeight|offsetLeft|offsetParent|offsetTop|offsetWidth|outerHTML|outerText|ownerDocument|parentElement|parentNode|previousElementSibling|previousSibling|querySelector|querySelectorAll|releasePointerCapture|removeAttribute|removeAttributeNS|removeAttributeNode|removeChild|removeEventListener|replaceChild|reportValidity|requestPointerLock|scrollHeight|scrollIntoView|scrollIntoViewIfNeeded|scrollLeft|scrollWidth|setAttribute|setAttributeNS|setAttributeNode|setAttributeNodeNS|setPointerCapture|shadowRoot|styleMap|tabIndex|tagName|textContent|toString|valueOf|(webkit|ms|moz|o)dropzone|(webkit|moz|ms|o)MatchesSelector|(webkit|moz|ms|o)RequestFullScreen|(webkit|moz|ms|o)RequestFullscreen)(\\s|$)',
-					),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							1,
-							4,
-							5,
-						),
-					),
-					'disallowed_ancestor' => array(
-						'amp-selector',
-					),
-					'reference_points' => array(
-						'AMP-SELECTOR child' => array(
-							'mandatory' => false,
-							'unique' => false,
-						),
-						'AMP-SELECTOR option' => array(
-							'mandatory' => false,
-							'unique' => false,
-						),
-					),
-					'requires_extension' => array(
-						'amp-selector',
-					),
-				),
-			),
-		),
-		'amp-sidebar' => array(
-			array(
-				'attr_spec_list' => array(
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'side' => array(
-						'value' => array(
-							'left',
-							'right',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							1,
-						),
-					),
-					'mandatory_parent' => 'body',
-					'requires_extension' => array(
-						'amp-sidebar',
-					),
-				),
-			),
-		),
-		'amp-skimlinks' => array(
-			array(
-				'attr_spec_list' => array(
-					'custom-tracking-id' => array(
-						'value_regex_casei' => '^.{0,50}$',
-					),
-					'excluded-domains' => array(),
-					'link-selector' => array(),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'publisher-code' => array(
-						'mandatory' => true,
-						'value_regex_casei' => '^[0-9]+X[0-9]+$',
-					),
-					'tracking' => array(
-						'value' => array(
-							'false',
-							'true',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							1,
-						),
-					),
-					'requires_extension' => array(
-						'amp-skimlinks',
-					),
-				),
-			),
-		),
-		'amp-social-share' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-share-endpoint' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'ftp',
-								'http',
-								'https',
-								'mailto',
-								'bbmi',
-								'fb-messenger',
-								'intent',
-								'line',
-								'skype',
-								'sms',
-								'snapchat',
-								'tel',
-								'tg',
-								'threema',
-								'viber',
-								'whatsapp',
-							),
-						),
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'type' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							5,
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-social-share',
-					),
-				),
-			),
-		),
-		'amp-soundcloud' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-color' => array(
-						'value_regex_casei' => '([0-9a-f]{3}){1,2}',
-					),
-					'data-playlistid' => array(
-						'value_regex' => '[0-9]+',
-					),
-					'data-secret-token' => array(
-						'value_regex' => '[A-Za-z0-9_-]+',
-					),
-					'data-trackid' => array(
-						'value_regex' => '[0-9]+',
-					),
-					'data-visual' => array(
-						'value_casei' => array(
-							'false',
-							'true',
-						),
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							3,
-						),
-					),
-					'requires_extension' => array(
-						'amp-soundcloud',
-					),
-				),
-			),
-		),
-		'amp-springboard-player' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-content-id' => array(
-						'mandatory' => true,
-					),
-					'data-domain' => array(
-						'mandatory' => true,
-					),
-					'data-items' => array(
-						'mandatory' => true,
-					),
-					'data-mode' => array(
-						'mandatory' => true,
-						'value_casei' => array(
-							'playlist',
-							'video',
-						),
-					),
-					'data-player-id' => array(
-						'mandatory' => true,
-						'value_regex_casei' => '[a-z0-9]+',
-					),
-					'data-site-id' => array(
-						'mandatory' => true,
-						'value_regex' => '[0-9]+',
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							7,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-springboard-player',
-					),
-				),
-			),
-		),
-		'amp-state' => array(
-			array(
-				'attr_spec_list' => array(
-					'[src]' => array(),
-					'credentials' => array(),
-					'id' => array(
-						'mandatory' => true,
-					),
-					'overridable' => array(),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => true,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-				),
-				'tag_spec' => array(
-					'requires_extension' => array(
-						'amp-bind',
-					),
-					'spec_name' => 'amp-state',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-bind',
-				),
-			),
-		),
-		'amp-sticky-ad' => array(
-			array(
-				'attr_spec_list' => array(
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							1,
-						),
-					),
-					'disallowed_ancestor' => array(
-						'amp-app-banner',
-					),
-					'requires_extension' => array(
-						'amp-sticky-ad',
-					),
-					'unique' => true,
-				),
-			),
-		),
-		'amp-story' => array(
-			array(
-				'attr_spec_list' => array(
-					'background-audio' => array(
-						'value_url' => array(
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
-					'bookend-config-src' => array(
-						'value_url' => array(
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
-					'poster-landscape-src' => array(
-						'value_url' => array(
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
-					'poster-portrait-src' => array(
-						'mandatory' => true,
-						'value_url' => array(
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
-					'poster-square-src' => array(
-						'value_url' => array(
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
-					'publisher' => array(
-						'mandatory' => true,
-					),
-					'publisher-logo-src' => array(
-						'mandatory' => true,
-						'value_url' => array(
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
-					'standalone' => array(
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'title' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'body',
-					'requires_extension' => array(
-						'amp-story',
-					),
-				),
-			),
-		),
-		'amp-story-access' => array(
-			array(
-				'attr_spec_list' => array(
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'type' => array(
-						'value' => array(
-							'blocking',
-							'notification',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'amp-story',
-					'requires_extension' => array(
-						'amp-access',
-					),
-				),
-			),
-		),
-		'amp-story-auto-ads' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(
-					'mandatory_parent' => 'amp-story',
-					'requires_extension' => array(
-						'amp-story-auto-ads',
-					),
-					'spec_url' => 'https://github.com/ampproject/amphtml/blob/master/extensions/amp-story/amp-story-auto-ads.md',
-					'unique' => true,
-				),
-			),
-		),
-		'amp-story-bookend' => array(
-			array(
-				'attr_spec_list' => array(
-					'layout' => array(
-						'mandatory' => true,
-						'value' => array(
-							'nodisplay',
-						),
-					),
-					'src' => array(
-						'value_url' => array(
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'amp-story',
-				),
-			),
-		),
-		'amp-story-consent' => array(
-			array(
-				'attr_spec_list' => array(
-					'id' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							1,
-						),
-					),
-					'mandatory_parent' => 'amp-consent',
-					'requires_extension' => array(
-						'amp-consent',
-						'amp-story',
-					),
-				),
-			),
-		),
-		'amp-story-cta-layer' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'amp-story-page',
-					'reference_points' => array(
-						'AMP-STORY-CTA-LAYER animate-in' => array(
-							'mandatory' => false,
-							'unique' => false,
-						),
-					),
-				),
-			),
-		),
-		'amp-story-grid-layer' => array(
-			array(
-				'attr_spec_list' => array(
-					'template' => array(
-						'mandatory' => true,
-						'value' => array(
-							'fill',
-							'horizontal',
-							'thirds',
-							'vertical',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'amp-story-page',
-					'reference_points' => array(
-						'AMP-STORY-GRID-LAYER animate-in' => array(
-							'mandatory' => false,
-							'unique' => false,
-						),
-						'AMP-STORY-GRID-LAYER default' => array(
-							'mandatory' => false,
-							'unique' => false,
-						),
-					),
-				),
-			),
-		),
-		'amp-story-page' => array(
-			array(
-				'attr_spec_list' => array(
-					'auto-advance-after' => array(),
-					'background-audio' => array(
-						'value_url' => array(
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
-					'id' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'amp-story',
-					'requires_extension' => array(
-						'amp-story',
-					),
-				),
-			),
-		),
-		'amp-timeago' => array(
-			array(
-				'attr_spec_list' => array(
-					'[datetime]' => array(),
-					'[title]' => array(),
-					'cutoff' => array(
-						'value_regex' => '\\d+',
-					),
-					'datetime' => array(
-						'mandatory' => true,
-						'value_regex' => '\\d{4}-[01]\\d-[0-3]\\dT[0-2]\\d:[0-5]\\d(:[0-5]\\d(\\.\\d+)?)?(Z|[+-][0-1][0-9]:[0-5][0-9])',
-					),
-					'locale' => array(),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							2,
-							3,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-timeago',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-timeago',
-				),
-			),
-		),
-		'amp-twitter' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-cards' => array(),
-					'data-conversation' => array(),
-					'data-limit' => array(),
-					'data-link-color' => array(),
-					'data-momentid' => array(
-						'value_regex' => '\\d+',
-					),
-					'data-theme' => array(),
-					'data-timeline-id' => array(
-						'value_regex' => '\\d+',
-					),
-					'data-timeline-owner-screen-name' => array(),
-					'data-timeline-screen-name' => array(),
-					'data-timeline-slug' => array(),
-					'data-timeline-source-type' => array(),
-					'data-timeline-url' => array(
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
-					'data-timeline-user-id' => array(
-						'value_regex' => '\\d+',
-					),
-					'data-tweetid' => array(),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							9,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-twitter',
-					),
-				),
-			),
-		),
-		'amp-user-notification' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-dismiss-href' => array(
-						'value_url' => array(
-							'allow_empty' => false,
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'data-show-if-href' => array(
-						'value_url' => array(
-							'allow_empty' => false,
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'enctype' => array(
-						'value' => array(
-							'application/x-www-form-urlencoded',
-						),
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							1,
-						),
-					),
-					'requires_extension' => array(
-						'amp-user-notification',
-					),
-				),
-			),
-		),
-		'amp-video' => array(
-			array(
-				'attr_spec_list' => array(
-					'[album]' => array(),
-					'[alt]' => array(),
-					'[artist]' => array(),
-					'[artwork]' => array(),
-					'[attribution]' => array(),
-					'[controls]' => array(),
-					'[controlslist]' => array(),
-					'[loop]' => array(),
-					'[poster]' => array(),
-					'[preload]' => array(),
-					'[src]' => array(),
-					'[title]' => array(),
-					'album' => array(),
-					'alt' => array(),
-					'artist' => array(),
-					'artwork' => array(),
-					'attribution' => array(),
-					'autoplay' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'controls' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'controlslist' => array(),
-					'crossorigin' => array(),
-					'disableremoteplayback' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'dock' => array(),
-					'lightbox' => array(),
-					'lightbox-thumbnail-id' => array(
-						'value_regex_casei' => '^[a-z][a-z\\d_-]*',
-					),
-					'loop' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'media' => array(),
-					'muted' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'noaudio' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'placeholder' => array(),
-					'poster' => array(),
-					'preload' => array(
-						'value' => array(
-							'auto',
-							'metadata',
-							'none',
-							'',
-						),
-					),
-					'rotate-to-fullscreen' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => true,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-				),
-				'tag_spec' => array(
-					'also_requires_tag_warning' => array(
-						'amp-video extension .js script',
-					),
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'disallowed_ancestor' => array(
-						'amp-story',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-video',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'[album]' => array(),
-					'[alt]' => array(),
-					'[artist]' => array(),
-					'[artwork]' => array(),
-					'[attribution]' => array(),
-					'[controls]' => array(),
-					'[controlslist]' => array(),
-					'[loop]' => array(),
-					'[poster]' => array(),
-					'[preload]' => array(),
-					'[src]' => array(),
-					'[title]' => array(),
-					'album' => array(),
-					'alt' => array(),
-					'artist' => array(),
-					'artwork' => array(),
-					'attribution' => array(),
-					'autoplay' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'controls' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'controlslist' => array(),
-					'crossorigin' => array(),
-					'disableremoteplayback' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'dock' => array(),
-					'loop' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'media' => array(),
-					'muted' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'noaudio' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'placeholder' => array(),
-					'poster' => array(
-						'mandatory' => true,
-					),
-					'preload' => array(
-						'value' => array(
-							'auto',
-							'metadata',
-							'none',
-							'',
-						),
-					),
-					'rotate-to-fullscreen' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => true,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'mandatory_ancestor' => 'amp-story',
-					'requires_extension' => array(
-						'amp-video',
-					),
-					'spec_name' => 'amp-story >> amp-video',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-video',
-				),
-			),
-		),
-		'amp-video-iframe' => array(
-			array(
-				'attr_spec_list' => array(
-					'album' => array(),
-					'alt' => array(),
-					'artist' => array(),
-					'artwork' => array(),
-					'attribution' => array(),
-					'autoplay' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'implements-media-session' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'implements-rotate-to-fullscreen' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'lightbox' => array(),
-					'lightbox-thumbnail-id' => array(
-						'value_regex_casei' => '^[a-z][a-z\\d_-]*',
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'poster' => array(
-						'mandatory' => true,
-					),
-					'referrerpolicy' => array(),
-					'rotate-to-fullscreen' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							9,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-video-iframe',
-					),
-					'spec_name' => 'AMP-VIDEO-IFRAME[poster]',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-video-iframe',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'album' => array(),
-					'alt' => array(),
-					'artist' => array(),
-					'artwork' => array(),
-					'attribution' => array(),
-					'autoplay' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'implements-media-session' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'implements-rotate-to-fullscreen' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'lightbox' => array(),
-					'lightbox-thumbnail-id' => array(
-						'value_regex_casei' => '^[a-z][a-z\\d_-]*',
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'referrerpolicy' => array(),
-					'rotate-to-fullscreen' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							9,
-							1,
-							4,
-						),
-					),
-					'reference_points' => array(
-						'AMP-VIDEO-IFRAME > [placeholder]' => array(
-							'mandatory' => true,
-							'unique' => true,
-						),
-					),
-					'requires_extension' => array(
-						'amp-video-iframe',
-					),
-					'spec_name' => 'AMP-VIDEO-IFRAME with [placeholder]',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-video-iframe',
-				),
-			),
-		),
-		'amp-vimeo' => array(
-			array(
-				'attr_spec_list' => array(
-					'autoplay' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'data-videoid' => array(
-						'mandatory' => true,
-						'value_regex' => '[0-9]+',
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-vimeo',
-					),
-				),
-			),
-		),
-		'amp-vine' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-vineid' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-vine',
-					),
-				),
-			),
-		),
-		'amp-viqeo-player' => array(
-			array(
-				'attr_spec_list' => array(
-					'autoplay' => array(),
-					'data-profileid' => array(
-						'mandatory' => true,
-						'value_regex' => '[0-9a-f]*',
-					),
-					'data-videoid' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-viqeo-player',
-					),
-				),
-			),
-		),
-		'amp-vk' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-embedtype' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							2,
-							7,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-vk',
-					),
-				),
-			),
-		),
-		'amp-web-push' => array(
-			array(
-				'attr_spec_list' => array(
-					'helper-iframe-url' => array(
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'id' => array(
-						'mandatory' => true,
-						'value' => array(
-							'amp-web-push',
-						),
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'permission-dialog-url' => array(
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'service-worker-url' => array(
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							1,
-						),
-					),
-					'requires_extension' => array(
-						'amp-web-push',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-web-push',
-				),
-			),
-		),
-		'amp-web-push-widget' => array(
-			array(
-				'attr_spec_list' => array(
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'visibility' => array(
-						'mandatory' => true,
-						'value' => array(
-							'blocked',
-							'subscribed',
-							'unsubscribed',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							2,
-						),
-					),
-					'requires_extension' => array(
-						'amp-web-push',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-web-push',
-				),
-			),
-		),
-		'amp-wistia-player' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-media-hashed-id' => array(
-						'mandatory' => true,
-						'value_regex' => '[0-9a-zA-Z]+',
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'rotate-to-fullscreen' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-wistia-player',
-					),
-				),
-			),
-		),
-		'amp-yotpo' => array(
-			array(
-				'attr_spec_list' => array(
-					'data-app-key' => array(
-						'mandatory' => true,
-					),
-					'data-widget-type' => array(
-						'mandatory' => true,
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-yotpo',
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-yotpo',
-				),
-			),
-		),
-		'amp-youtube' => array(
-			array(
-				'attr_spec_list' => array(
-					'[data-videoid]' => array(),
-					'autoplay' => array(),
-					'credentials' => array(
-						'value_casei' => array(
-							'include',
-							'omit',
-						),
-					),
-					'data-live-channelid' => array(
-						'value_regex' => '[^=/?:]+',
-					),
-					'data-videoid' => array(
-						'value_regex' => '[^=/?:]+',
-					),
-					'lightbox' => array(),
-					'lightbox-thumbnail-id' => array(
-						'value_regex_casei' => '^[a-z][a-z\\d_-]*',
-					),
-					'media' => array(),
-					'noloading' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'amp_layout' => array(
-						'supported_layouts' => array(
-							6,
-							2,
-							3,
-							7,
-							1,
-							4,
-						),
-					),
-					'requires_extension' => array(
-						'amp-youtube',
-					),
-				),
-			),
-		),
-		'article' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'aside' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'audio' => array(
-			array(
-				'attr_spec_list' => array(
-					'autoplay' => array(),
-					'controls' => array(),
-					'loop' => array(),
-					'muted' => array(),
-					'preload' => array(),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'data',
-								'https',
-							),
-						),
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'noscript',
-					'mandatory_ancestor_suggested_alternative' => 'amp-audio',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-audio',
-				),
-			),
-		),
-		'b' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'base' => array(
-			array(
-				'attr_spec_list' => array(
-					'href' => array(
-						'value' => array(
-							'/',
-						),
-					),
-					'target' => array(
-						'value_casei' => array(
-							'_blank',
-							'_self',
-							'_top',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'head',
-					'unique' => true,
-				),
-			),
-		),
-		'bdi' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'bdo' => array(
-			array(
-				'attr_spec_list' => array(
-					'dir' => array(),
-				),
-				'tag_spec' => array(),
-			),
-		),
-		'big' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'blockquote' => array(
-			array(
-				'attr_spec_list' => array(
-					'align' => array(),
-					'cite' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_empty' => true,
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
-				),
-				'tag_spec' => array(),
-			),
-		),
-		'body' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(
-					'mandatory' => true,
-					'mandatory_parent' => 'html',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#required-markup',
-					'unique' => true,
-				),
-			),
-		),
-		'br' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'button' => array(
-			array(
-				'attr_spec_list' => array(
-					'[disabled]' => array(),
-					'[type]' => array(),
-					'[value]' => array(),
-					'disabled' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'name' => array(
-						'blacklisted_value_regex' => '(^|\\s)(__amp_\\S*|__count__|__defineGetter__|__defineSetter__|__lookupGetter__|__lookupSetter__|__noSuchMethod__|__parent__|__proto__|__AMP_\\S*|\\$p|\\$proxy|acceptCharset|addEventListener|appendChild|assignedSlot|attachShadow|baseURI|checkValidity|childElementCount|childNodes|classList|className|clientHeight|clientLeft|clientTop|clientWidth|compareDocumentPosition|computedName|computedRole|contentEditable|createShadowRoot|enqueAction|firstChild|firstElementChild|getAnimations|getAttribute|getAttributeNS|getAttributeNode|getAttributeNodeNS|getBoundingClientRect|getClientRects|getDestinationInsertionPoints|getElementsByClassName|getElementsByTagName|getElementsByTagNameNS|getRootNode|hasAttribute|hasAttributeNS|hasAttributes|hasChildNodes|hasPointerCapture|innerHTML|innerText|inputMode|insertAdjacentElement|insertAdjacentHTML|insertAdjacentText|isContentEditable|isDefaultNamespace|isEqualNode|isSameNode|lastChild|lastElementChild|lookupNamespaceURI|namespaceURI|nextElementSibling|nextSibling|nodeName|nodeType|nodeValue|offsetHeight|offsetLeft|offsetParent|offsetTop|offsetWidth|outerHTML|outerText|ownerDocument|parentElement|parentNode|previousElementSibling|previousSibling|querySelector|querySelectorAll|releasePointerCapture|removeAttribute|removeAttributeNS|removeAttributeNode|removeChild|removeEventListener|replaceChild|reportValidity|requestPointerLock|scrollHeight|scrollIntoView|scrollIntoViewIfNeeded|scrollLeft|scrollWidth|setAttribute|setAttributeNS|setAttributeNode|setAttributeNodeNS|setPointerCapture|shadowRoot|styleMap|tabIndex|tagName|textContent|toString|valueOf|(webkit|ms|moz|o)dropzone|(webkit|moz|ms|o)MatchesSelector|(webkit|moz|ms|o)RequestFullScreen|(webkit|moz|ms|o)RequestFullscreen)(\\s|$)',
-					),
-					'role' => array(),
-					'tabindex' => array(),
-					'type' => array(),
-					'value' => array(),
-				),
-				'tag_spec' => array(),
-			),
-			array(
-				'attr_spec_list' => array(
-					'name' => array(
-						'blacklisted_value_regex' => '(^|\\s)(__amp_\\S*|__count__|__defineGetter__|__defineSetter__|__lookupGetter__|__lookupSetter__|__noSuchMethod__|__parent__|__proto__|__AMP_\\S*|\\$p|\\$proxy|acceptCharset|addEventListener|appendChild|assignedSlot|attachShadow|baseURI|checkValidity|childElementCount|childNodes|classList|className|clientHeight|clientLeft|clientTop|clientWidth|compareDocumentPosition|computedName|computedRole|contentEditable|createShadowRoot|enqueAction|firstChild|firstElementChild|getAnimations|getAttribute|getAttributeNS|getAttributeNode|getAttributeNodeNS|getBoundingClientRect|getClientRects|getDestinationInsertionPoints|getElementsByClassName|getElementsByTagName|getElementsByTagNameNS|getRootNode|hasAttribute|hasAttributeNS|hasAttributes|hasChildNodes|hasPointerCapture|innerHTML|innerText|inputMode|insertAdjacentElement|insertAdjacentHTML|insertAdjacentText|isContentEditable|isDefaultNamespace|isEqualNode|isSameNode|lastChild|lastElementChild|lookupNamespaceURI|namespaceURI|nextElementSibling|nextSibling|nodeName|nodeType|nodeValue|offsetHeight|offsetLeft|offsetParent|offsetTop|offsetWidth|outerHTML|outerText|ownerDocument|parentElement|parentNode|previousElementSibling|previousSibling|querySelector|querySelectorAll|releasePointerCapture|removeAttribute|removeAttributeNS|removeAttributeNode|removeChild|removeEventListener|replaceChild|reportValidity|requestPointerLock|scrollHeight|scrollIntoView|scrollIntoViewIfNeeded|scrollLeft|scrollWidth|setAttribute|setAttributeNS|setAttributeNode|setAttributeNodeNS|setPointerCapture|shadowRoot|styleMap|tabIndex|tagName|textContent|toString|valueOf|(webkit|ms|moz|o)dropzone|(webkit|moz|ms|o)MatchesSelector|(webkit|moz|ms|o)RequestFullScreen|(webkit|moz|ms|o)RequestFullscreen)(\\s|$)',
-					),
-					'open-button' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'role' => array(),
-					'tabindex' => array(),
-					'type' => array(),
-					'value' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'amp-app-banner',
-					'spec_name' => 'amp-app-banner button[open-button]',
-				),
-			),
-		),
-		'caption' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'center' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'circle' => array(
-			array(
-				'attr_spec_list' => array(
-					'alignment-baseline' => array(),
-					'baseline-shift' => array(),
-					'clip' => array(),
-					'clip-path' => array(),
-					'clip-rule' => array(),
-					'color' => array(),
-					'color-interpolation' => array(),
-					'color-interpolation-filters' => array(),
-					'color-profile' => array(),
-					'color-rendering' => array(),
-					'cursor' => array(),
-					'cx' => array(),
-					'cy' => array(),
-					'direction' => array(),
-					'display' => array(),
-					'dominant-baseline' => array(),
-					'enable-background' => array(),
-					'externalresourcesrequired' => array(),
-					'fill' => array(),
-					'fill-opacity' => array(),
-					'fill-rule' => array(),
-					'filter' => array(),
-					'flood-color' => array(),
-					'flood-opacity' => array(),
-					'focusable' => array(),
-					'font-family' => array(),
-					'font-size' => array(),
-					'font-size-adjust' => array(),
-					'font-stretch' => array(),
-					'font-style' => array(),
-					'font-variant' => array(),
-					'font-weight' => array(),
-					'glyph-orientation-horizontal' => array(),
-					'glyph-orientation-vertical' => array(),
-					'image-rendering' => array(),
-					'kerning' => array(),
-					'letter-spacing' => array(),
-					'lighting-color' => array(),
-					'marker-end' => array(),
-					'marker-mid' => array(),
-					'marker-start' => array(),
-					'mask' => array(),
-					'opacity' => array(),
-					'overflow' => array(),
-					'pointer-events' => array(),
-					'r' => array(),
-					'requiredextensions' => array(),
-					'requiredfeatures' => array(),
-					'shape-rendering' => array(),
-					'sketch:type' => array(),
-					'stop-color' => array(),
-					'stop-opacity' => array(),
-					'stroke' => array(),
-					'stroke-dasharray' => array(),
-					'stroke-dashoffset' => array(),
-					'stroke-linecap' => array(),
-					'stroke-linejoin' => array(),
-					'stroke-miterlimit' => array(),
-					'stroke-opacity' => array(),
-					'stroke-width' => array(),
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'systemlanguage' => array(),
-					'text-anchor' => array(),
-					'text-decoration' => array(),
-					'text-rendering' => array(),
-					'transform' => array(),
-					'unicode-bidi' => array(),
-					'vector-effect' => array(),
-					'visibility' => array(),
-					'word-spacing' => array(),
-					'writing-mode' => array(),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'svg',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'cite' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'clippath' => array(
-			array(
-				'attr_spec_list' => array(
-					'alignment-baseline' => array(),
-					'baseline-shift' => array(),
-					'clip' => array(),
-					'clip-path' => array(),
-					'clip-rule' => array(),
-					'clippathunits' => array(),
-					'color' => array(),
-					'color-interpolation' => array(),
-					'color-interpolation-filters' => array(),
-					'color-profile' => array(),
-					'color-rendering' => array(),
-					'cursor' => array(),
-					'direction' => array(),
-					'display' => array(),
-					'dominant-baseline' => array(),
-					'enable-background' => array(),
-					'externalresourcesrequired' => array(),
-					'fill' => array(),
-					'fill-opacity' => array(),
-					'fill-rule' => array(),
-					'filter' => array(),
-					'flood-color' => array(),
-					'flood-opacity' => array(),
-					'focusable' => array(),
-					'font-family' => array(),
-					'font-size' => array(),
-					'font-size-adjust' => array(),
-					'font-stretch' => array(),
-					'font-style' => array(),
-					'font-variant' => array(),
-					'font-weight' => array(),
-					'glyph-orientation-horizontal' => array(),
-					'glyph-orientation-vertical' => array(),
-					'image-rendering' => array(),
-					'kerning' => array(),
-					'letter-spacing' => array(),
-					'lighting-color' => array(),
-					'marker-end' => array(),
-					'marker-mid' => array(),
-					'marker-start' => array(),
-					'mask' => array(),
-					'opacity' => array(),
-					'overflow' => array(),
-					'pointer-events' => array(),
-					'requiredextensions' => array(),
-					'requiredfeatures' => array(),
-					'shape-rendering' => array(),
-					'stop-color' => array(),
-					'stop-opacity' => array(),
-					'stroke' => array(),
-					'stroke-dasharray' => array(),
-					'stroke-dashoffset' => array(),
-					'stroke-linecap' => array(),
-					'stroke-linejoin' => array(),
-					'stroke-miterlimit' => array(),
-					'stroke-opacity' => array(),
-					'stroke-width' => array(),
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'systemlanguage' => array(),
-					'text-anchor' => array(),
-					'text-decoration' => array(),
-					'text-rendering' => array(),
-					'transform' => array(),
-					'unicode-bidi' => array(),
-					'vector-effect' => array(),
-					'visibility' => array(),
-					'word-spacing' => array(),
-					'writing-mode' => array(),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'svg',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'code' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'col' => array(
-			array(
-				'attr_spec_list' => array(
-					'span' => array(),
-				),
-				'tag_spec' => array(),
-			),
-		),
-		'colgroup' => array(
-			array(
-				'attr_spec_list' => array(
-					'span' => array(),
-				),
-				'tag_spec' => array(),
-			),
-		),
-		'data' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'datalist' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-form',
-				),
-			),
-		),
-		'dd' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'defs' => array(
-			array(
-				'attr_spec_list' => array(
-					'alignment-baseline' => array(),
-					'baseline-shift' => array(),
-					'clip' => array(),
-					'clip-path' => array(),
-					'clip-rule' => array(),
-					'color' => array(),
-					'color-interpolation' => array(),
-					'color-interpolation-filters' => array(),
-					'color-profile' => array(),
-					'color-rendering' => array(),
-					'cursor' => array(),
-					'direction' => array(),
-					'display' => array(),
-					'dominant-baseline' => array(),
-					'enable-background' => array(),
-					'externalresourcesrequired' => array(),
-					'fill' => array(),
-					'fill-opacity' => array(),
-					'fill-rule' => array(),
-					'filter' => array(),
-					'flood-color' => array(),
-					'flood-opacity' => array(),
-					'focusable' => array(),
-					'font-family' => array(),
-					'font-size' => array(),
-					'font-size-adjust' => array(),
-					'font-stretch' => array(),
-					'font-style' => array(),
-					'font-variant' => array(),
-					'font-weight' => array(),
-					'glyph-orientation-horizontal' => array(),
-					'glyph-orientation-vertical' => array(),
-					'image-rendering' => array(),
-					'kerning' => array(),
-					'letter-spacing' => array(),
-					'lighting-color' => array(),
-					'marker-end' => array(),
-					'marker-mid' => array(),
-					'marker-start' => array(),
-					'mask' => array(),
-					'opacity' => array(),
-					'overflow' => array(),
-					'pointer-events' => array(),
-					'requiredextensions' => array(),
-					'requiredfeatures' => array(),
-					'shape-rendering' => array(),
-					'stop-color' => array(),
-					'stop-opacity' => array(),
-					'stroke' => array(),
-					'stroke-dasharray' => array(),
-					'stroke-dashoffset' => array(),
-					'stroke-linecap' => array(),
-					'stroke-linejoin' => array(),
-					'stroke-miterlimit' => array(),
-					'stroke-opacity' => array(),
-					'stroke-width' => array(),
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'systemlanguage' => array(),
-					'text-anchor' => array(),
-					'text-decoration' => array(),
-					'text-rendering' => array(),
-					'transform' => array(),
-					'unicode-bidi' => array(),
-					'vector-effect' => array(),
-					'visibility' => array(),
-					'word-spacing' => array(),
-					'writing-mode' => array(),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'svg',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'del' => array(
-			array(
-				'attr_spec_list' => array(
-					'cite' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_empty' => true,
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
-					'datetime' => array(),
-				),
-				'tag_spec' => array(),
-			),
-		),
-		'desc' => array(
-			array(
-				'attr_spec_list' => array(
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'svg',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'dfn' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'dir' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'div' => array(
-			array(
-				'attr_spec_list' => array(
-					'align' => array(),
-				),
-				'tag_spec' => array(),
-			),
-			array(
-				'attr_spec_list' => array(
-					'align' => array(),
-					'verify-error' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'form',
-					'spec_name' => 'FORM DIV [verify-error]',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'align' => array(),
-					'template' => array(
-						'mandatory' => true,
-					),
-					'verify-error' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'form',
-					'spec_name' => 'FORM DIV [verify-error][template]',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'align' => array(),
-					'submitting' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'form',
-					'spec_name' => 'FORM DIV [submitting]',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'align' => array(),
-					'submitting' => array(
-						'mandatory' => true,
-					),
-					'template' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'form',
-					'spec_name' => 'FORM DIV [submitting][template]',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'align' => array(),
-					'submit-success' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'form',
-					'spec_name' => 'FORM DIV [submit-success]',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'align' => array(),
-					'submit-success' => array(
-						'mandatory' => true,
-					),
-					'template' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'form',
-					'spec_name' => 'FORM DIV [submit-success][template]',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'align' => array(),
-					'submit-error' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'form',
-					'spec_name' => 'FORM DIV [submit-error]',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'align' => array(),
-					'submit-error' => array(
-						'mandatory' => true,
-					),
-					'template' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'form',
-					'spec_name' => 'FORM DIV [submit-error][template]',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'first' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'amp-image-slider',
-					'spec_name' => 'AMP-IMAGE-SLIDER > DIV [first]',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-image-slider',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'second' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'amp-image-slider',
-					'spec_name' => 'AMP-IMAGE-SLIDER > DIV [second]',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-image-slider',
-				),
-			),
-		),
-		'dl' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'dt' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'ellipse' => array(
-			array(
-				'attr_spec_list' => array(
-					'alignment-baseline' => array(),
-					'baseline-shift' => array(),
-					'clip' => array(),
-					'clip-path' => array(),
-					'clip-rule' => array(),
-					'color' => array(),
-					'color-interpolation' => array(),
-					'color-interpolation-filters' => array(),
-					'color-profile' => array(),
-					'color-rendering' => array(),
-					'cursor' => array(),
-					'cx' => array(),
-					'cy' => array(),
-					'direction' => array(),
-					'display' => array(),
-					'dominant-baseline' => array(),
-					'enable-background' => array(),
-					'externalresourcesrequired' => array(),
-					'fill' => array(),
-					'fill-opacity' => array(),
-					'fill-rule' => array(),
-					'filter' => array(),
-					'flood-color' => array(),
-					'flood-opacity' => array(),
-					'focusable' => array(),
-					'font-family' => array(),
-					'font-size' => array(),
-					'font-size-adjust' => array(),
-					'font-stretch' => array(),
-					'font-style' => array(),
-					'font-variant' => array(),
-					'font-weight' => array(),
-					'glyph-orientation-horizontal' => array(),
-					'glyph-orientation-vertical' => array(),
-					'image-rendering' => array(),
-					'kerning' => array(),
-					'letter-spacing' => array(),
-					'lighting-color' => array(),
-					'marker-end' => array(),
-					'marker-mid' => array(),
-					'marker-start' => array(),
-					'mask' => array(),
-					'opacity' => array(),
-					'overflow' => array(),
-					'pointer-events' => array(),
-					'requiredextensions' => array(),
-					'requiredfeatures' => array(),
-					'rx' => array(),
-					'ry' => array(),
-					'shape-rendering' => array(),
-					'sketch:type' => array(),
-					'stop-color' => array(),
-					'stop-opacity' => array(),
-					'stroke' => array(),
-					'stroke-dasharray' => array(),
-					'stroke-dashoffset' => array(),
-					'stroke-linecap' => array(),
-					'stroke-linejoin' => array(),
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-					),
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-					'display' => array(),
-					'dominant-baseline' => array(),
-					'enable-background' => array(),
-					'externalresourcesrequired' => array(),
-					'fill' => array(),
-					'fill-opacity' => array(),
-					'fill-rule' => array(),
-					'filter' => array(),
-					'filterres' => array(),
-					'filterunits' => array(),
-					'flood-color' => array(),
-					'flood-opacity' => array(),
-					'focusable' => array(),
-					'font-family' => array(),
-					'font-size' => array(),
-					'font-size-adjust' => array(),
-					'font-stretch' => array(),
-					'font-style' => array(),
-					'font-variant' => array(),
-					'font-weight' => array(),
-					'glyph-orientation-horizontal' => array(),
-					'glyph-orientation-vertical' => array(),
-					'height' => array(),
-					'image-rendering' => array(),
-					'kerning' => array(),
-					'letter-spacing' => array(),
-					'lighting-color' => array(),
-					'marker-end' => array(),
-					'marker-mid' => array(),
-					'marker-start' => array(),
-					'mask' => array(),
-					'opacity' => array(),
-					'overflow' => array(),
-					'pointer-events' => array(),
-					'primitiveunits' => array(),
-					'shape-rendering' => array(),
-					'stop-color' => array(),
-					'stop-opacity' => array(),
-					'stroke' => array(),
-					'stroke-dasharray' => array(),
-					'stroke-dashoffset' => array(),
-					'stroke-linecap' => array(),
-					'stroke-linejoin' => array(),
-					'stroke-miterlimit' => array(),
-					'stroke-opacity' => array(),
-					'stroke-width' => array(),
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'text-anchor' => array(),
-					'text-decoration' => array(),
-					'text-rendering' => array(),
-					'unicode-bidi' => array(),
-					'vector-effect' => array(),
-					'visibility' => array(),
-					'width' => array(),
-					'word-spacing' => array(),
-					'writing-mode' => array(),
-					'x' => array(),
-					'xlink:actuate' => array(),
-					'xlink:arcrole' => array(),
-					'xlink:href' => array(
-						'alternative_names' => array(
-							'href',
-						),
-						'value_url' => array(
-							'allow_empty' => false,
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
-					'xlink:role' => array(),
-					'xlink:show' => array(),
-					'xlink:title' => array(),
-					'xlink:type' => array(),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-					'y' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'svg',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'footer' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'form' => array(
-			array(
-				'attr_spec_list' => array(
-					'accept' => array(),
-					'accept-charset' => array(),
-					'action' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'action-xhr' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'autocomplete' => array(),
-					'custom-validation-reporting' => array(
-						'value' => array(
-							'as-you-go',
-							'interact-and-submit',
-							'show-all-on-submit',
-							'show-first-on-submit',
-						),
-					),
-					'enctype' => array(),
-					'method' => array(
-						'value_casei' => array(
-							'get',
-						),
-					),
-					'name' => array(),
-					'novalidate' => array(),
-					'target' => array(
-						'mandatory' => true,
-						'value_casei' => array(
-							'_blank',
-							'_top',
-						),
-					),
-					'verify-xhr' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-				),
-				'tag_spec' => array(
-					'disallowed_ancestor' => array(
-						'amp-app-banner',
-					),
-					'requires_extension' => array(
-						'amp-form',
-					),
-					'spec_name' => 'FORM [method=GET]',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'accept' => array(),
-					'accept-charset' => array(),
-					'action-xhr' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'autocomplete' => array(),
-					'custom-validation-reporting' => array(
-						'value' => array(
-							'as-you-go',
-							'interact-and-submit',
-							'show-all-on-submit',
-							'show-first-on-submit',
-						),
-					),
-					'enctype' => array(),
-					'method' => array(
-						'dispatch_key' => 2,
-						'mandatory' => true,
-						'value_casei' => array(
-							'post',
-						),
-					),
-					'name' => array(),
-					'novalidate' => array(),
-					'target' => array(
-						'value_casei' => array(
-							'_blank',
-							'_top',
-						),
-					),
-					'verify-xhr' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-				),
-				'tag_spec' => array(
-					'disallowed_ancestor' => array(
-						'amp-app-banner',
-					),
-					'requires_extension' => array(
-						'amp-form',
-					),
-					'spec_name' => 'FORM [method=POST]',
-				),
-			),
-		),
-		'g' => array(
-			array(
-				'attr_spec_list' => array(
-					'alignment-baseline' => array(),
-					'baseline-shift' => array(),
-					'clip' => array(),
-					'clip-path' => array(),
-					'clip-rule' => array(),
-					'color' => array(),
-					'color-interpolation' => array(),
-					'color-interpolation-filters' => array(),
-					'color-profile' => array(),
-					'color-rendering' => array(),
-					'cursor' => array(),
-					'direction' => array(),
-					'display' => array(),
-					'dominant-baseline' => array(),
-					'enable-background' => array(),
-					'externalresourcesrequired' => array(),
-					'fill' => array(),
-					'fill-opacity' => array(),
-					'fill-rule' => array(),
-					'filter' => array(),
-					'flood-color' => array(),
-					'flood-opacity' => array(),
-					'focusable' => array(),
-					'font-family' => array(),
-					'font-size' => array(),
-					'font-size-adjust' => array(),
-					'font-stretch' => array(),
-					'font-style' => array(),
-					'font-variant' => array(),
-					'font-weight' => array(),
-					'glyph-orientation-horizontal' => array(),
-					'glyph-orientation-vertical' => array(),
-					'image-rendering' => array(),
-					'kerning' => array(),
-					'letter-spacing' => array(),
-					'lighting-color' => array(),
-					'marker-end' => array(),
-					'marker-mid' => array(),
-					'marker-start' => array(),
-					'mask' => array(),
-					'opacity' => array(),
-					'overflow' => array(),
-					'pointer-events' => array(),
-					'requiredextensions' => array(),
-					'requiredfeatures' => array(),
-					'shape-rendering' => array(),
-					'stop-color' => array(),
-					'stop-opacity' => array(),
-					'stroke' => array(),
-					'stroke-dasharray' => array(),
-					'stroke-dashoffset' => array(),
-					'stroke-linecap' => array(),
-					'stroke-linejoin' => array(),
-					'stroke-miterlimit' => array(),
-					'stroke-opacity' => array(),
-					'stroke-width' => array(),
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'systemlanguage' => array(),
-					'text-anchor' => array(),
-					'text-decoration' => array(),
-					'text-rendering' => array(),
-					'transform' => array(),
-					'unicode-bidi' => array(),
-					'vector-effect' => array(),
-					'visibility' => array(),
-					'word-spacing' => array(),
-					'writing-mode' => array(),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'svg',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'glyph' => array(
-			array(
-				'attr_spec_list' => array(
-					'alignment-baseline' => array(),
-					'arabic-form' => array(),
-					'baseline-shift' => array(),
-					'clip' => array(),
-					'clip-path' => array(),
-					'clip-rule' => array(),
-					'color' => array(),
-					'color-interpolation' => array(),
-					'color-interpolation-filters' => array(),
-					'color-profile' => array(),
-					'color-rendering' => array(),
-					'cursor' => array(),
-					'd' => array(),
-					'direction' => array(),
-					'display' => array(),
-					'dominant-baseline' => array(),
-					'enable-background' => array(),
-					'fill' => array(),
-					'fill-opacity' => array(),
-					'fill-rule' => array(),
-					'filter' => array(),
-					'flood-color' => array(),
-					'flood-opacity' => array(),
-					'focusable' => array(),
-					'font-family' => array(),
-					'font-size' => array(),
-					'font-size-adjust' => array(),
-					'font-stretch' => array(),
-					'font-style' => array(),
-					'font-variant' => array(),
-					'font-weight' => array(),
-					'glyph-name' => array(),
-					'glyph-orientation-horizontal' => array(),
-					'glyph-orientation-vertical' => array(),
-					'horiz-adv-x' => array(),
-					'image-rendering' => array(),
-					'kerning' => array(),
-					'letter-spacing' => array(),
-					'lighting-color' => array(),
-					'marker-end' => array(),
-					'marker-mid' => array(),
-					'marker-start' => array(),
-					'mask' => array(),
-					'opacity' => array(),
-					'orientation' => array(),
-					'overflow' => array(),
-					'pointer-events' => array(),
-					'shape-rendering' => array(),
-					'stop-color' => array(),
-					'stop-opacity' => array(),
-					'stroke' => array(),
-					'stroke-dasharray' => array(),
-					'stroke-dashoffset' => array(),
-					'stroke-linecap' => array(),
-					'stroke-linejoin' => array(),
-					'stroke-miterlimit' => array(),
-					'stroke-opacity' => array(),
-					'stroke-width' => array(),
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'text-anchor' => array(),
-					'text-decoration' => array(),
-					'text-rendering' => array(),
-					'unicode' => array(),
-					'unicode-bidi' => array(),
-					'vector-effect' => array(),
-					'vert-adv-y' => array(),
-					'vert-origin-x' => array(),
-					'vert-origin-y' => array(),
-					'visibility' => array(),
-					'word-spacing' => array(),
-					'writing-mode' => array(),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'svg',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'glyphref' => array(
-			array(
-				'attr_spec_list' => array(
-					'alignment-baseline' => array(),
-					'baseline-shift' => array(),
-					'clip' => array(),
-					'clip-path' => array(),
-					'clip-rule' => array(),
-					'color' => array(),
-					'color-interpolation' => array(),
-					'color-interpolation-filters' => array(),
-					'color-profile' => array(),
-					'color-rendering' => array(),
-					'cursor' => array(),
-					'direction' => array(),
-					'display' => array(),
-					'dominant-baseline' => array(),
-					'dx' => array(),
-					'dy' => array(),
-					'enable-background' => array(),
-					'fill' => array(),
-					'fill-opacity' => array(),
-					'fill-rule' => array(),
-					'filter' => array(),
-					'flood-color' => array(),
-					'flood-opacity' => array(),
-					'focusable' => array(),
-					'font-family' => array(),
-					'font-size' => array(),
-					'font-size-adjust' => array(),
-					'font-stretch' => array(),
-					'font-style' => array(),
-					'font-variant' => array(),
-					'font-weight' => array(),
-					'format' => array(),
-					'glyph-orientation-horizontal' => array(),
-					'glyph-orientation-vertical' => array(),
-					'glyphref' => array(),
-					'image-rendering' => array(),
-					'kerning' => array(),
-					'letter-spacing' => array(),
-					'lighting-color' => array(),
-					'marker-end' => array(),
-					'marker-mid' => array(),
-					'marker-start' => array(),
-					'mask' => array(),
-					'opacity' => array(),
-					'overflow' => array(),
-					'pointer-events' => array(),
-					'shape-rendering' => array(),
-					'stop-color' => array(),
-					'stop-opacity' => array(),
-					'stroke' => array(),
-					'stroke-dasharray' => array(),
-					'stroke-dashoffset' => array(),
-					'stroke-linecap' => array(),
-					'stroke-linejoin' => array(),
-					'stroke-miterlimit' => array(),
-					'stroke-opacity' => array(),
-					'stroke-width' => array(),
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'text-anchor' => array(),
-					'text-decoration' => array(),
-					'text-rendering' => array(),
-					'unicode-bidi' => array(),
-					'vector-effect' => array(),
-					'visibility' => array(),
-					'word-spacing' => array(),
-					'writing-mode' => array(),
-					'x' => array(),
-					'xlink:actuate' => array(),
-					'xlink:arcrole' => array(),
-					'xlink:href' => array(
-						'alternative_names' => array(
-							'href',
-						),
-						'value_url' => array(
-							'allow_empty' => false,
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
-					'xlink:role' => array(),
-					'xlink:show' => array(),
-					'xlink:title' => array(),
-					'xlink:type' => array(),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-					'y' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'svg',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'h1' => array(
-			array(
-				'attr_spec_list' => array(
-					'align' => array(),
-				),
-				'tag_spec' => array(),
-			),
-		),
-		'h2' => array(
-			array(
-				'attr_spec_list' => array(
-					'align' => array(),
-				),
-				'tag_spec' => array(),
-			),
-		),
-		'h3' => array(
-			array(
-				'attr_spec_list' => array(
-					'align' => array(),
-				),
-				'tag_spec' => array(),
-			),
-		),
-		'h4' => array(
-			array(
-				'attr_spec_list' => array(
-					'align' => array(),
-				),
-				'tag_spec' => array(),
-			),
-		),
-		'h5' => array(
-			array(
-				'attr_spec_list' => array(
-					'align' => array(),
-				),
-				'tag_spec' => array(),
-			),
-		),
-		'h6' => array(
-			array(
-				'attr_spec_list' => array(
-					'align' => array(),
-				),
-				'tag_spec' => array(),
-			),
-		),
-		'head' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(
-					'mandatory' => true,
-					'mandatory_parent' => 'html',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#required-markup',
-					'unique' => true,
-				),
-			),
-		),
-		'header' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'hgroup' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'hkern' => array(
-			array(
-				'attr_spec_list' => array(
-					'g1' => array(),
-					'g2' => array(),
-					'k' => array(),
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'u1' => array(),
-					'u2' => array(),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'svg',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'hr' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'html' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(
-					'mandatory' => true,
-					'mandatory_parent' => '!doctype',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#required-markup',
-					'unique' => true,
-				),
-			),
-		),
-		'i' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'iframe' => array(
-			array(
-				'attr_spec_list' => array(
-					'frameborder' => array(
-						'value' => array(
-							'0',
-							'1',
-						),
-					),
-					'height' => array(),
-					'name' => array(),
-					'referrerpolicy' => array(),
-					'resizable' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'sandbox' => array(),
-					'scrolling' => array(
-						'value' => array(
-							'auto',
-							'yes',
-							'no',
-						),
-					),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'data',
-								'https',
-							),
-						),
-					),
-					'srcdoc' => array(),
-					'width' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'noscript',
-					'mandatory_ancestor_suggested_alternative' => 'amp-iframe',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-iframe',
-				),
-			),
-		),
-		'image' => array(
-			array(
-				'attr_spec_list' => array(
-					'alignment-baseline' => array(),
-					'baseline-shift' => array(),
-					'clip' => array(),
-					'clip-path' => array(),
-					'clip-rule' => array(),
-					'color' => array(),
-					'color-interpolation' => array(),
-					'color-interpolation-filters' => array(),
-					'color-profile' => array(),
-					'color-rendering' => array(),
-					'cursor' => array(),
-					'direction' => array(),
-					'display' => array(),
-					'dominant-baseline' => array(),
-					'enable-background' => array(),
-					'externalresourcesrequired' => array(),
-					'fill' => array(),
-					'fill-opacity' => array(),
-					'fill-rule' => array(),
-					'filter' => array(),
-					'flood-color' => array(),
-					'flood-opacity' => array(),
-					'focusable' => array(),
-					'font-family' => array(),
-					'font-size' => array(),
-					'font-size-adjust' => array(),
-					'font-stretch' => array(),
-					'font-style' => array(),
-					'font-variant' => array(),
-					'font-weight' => array(),
-					'glyph-orientation-horizontal' => array(),
-					'glyph-orientation-vertical' => array(),
-					'height' => array(),
-					'image-rendering' => array(),
-					'kerning' => array(),
-					'letter-spacing' => array(),
-					'lighting-color' => array(),
-					'marker-end' => array(),
-					'marker-mid' => array(),
-					'marker-start' => array(),
-					'mask' => array(),
-					'opacity' => array(),
-					'overflow' => array(),
-					'pointer-events' => array(),
-					'preserveaspectratio' => array(),
-					'requiredextensions' => array(),
-					'requiredfeatures' => array(),
-					'shape-rendering' => array(),
-					'stop-color' => array(),
-					'stop-opacity' => array(),
-					'stroke' => array(),
-					'stroke-dasharray' => array(),
-					'stroke-dashoffset' => array(),
-					'stroke-linecap' => array(),
-					'stroke-linejoin' => array(),
-					'stroke-miterlimit' => array(),
-					'stroke-opacity' => array(),
-					'stroke-width' => array(),
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'systemlanguage' => array(),
-					'text-anchor' => array(),
-					'text-decoration' => array(),
-					'text-rendering' => array(),
-					'transform' => array(),
-					'unicode-bidi' => array(),
-					'vector-effect' => array(),
-					'visibility' => array(),
-					'width' => array(),
-					'word-spacing' => array(),
-					'writing-mode' => array(),
-					'x' => array(),
-					'xlink:actuate' => array(),
-					'xlink:arcrole' => array(),
-					'xlink:href' => array(
-						'alternative_names' => array(
-							'href',
-						),
-						'blacklisted_value_regex' => '(^|\\s)data:image\\/svg\\+xml',
-						'value_url' => array(
-							'allow_empty' => false,
-							'protocol' => array(
-								'data',
-								'http',
-								'https',
-							),
-						),
-					),
-					'xlink:role' => array(),
-					'xlink:show' => array(),
-					'xlink:title' => array(),
-					'xlink:type' => array(),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-					'y' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'svg',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'img' => array(
-			array(
-				'attr_spec_list' => array(
-					'alt' => array(),
-					'attribution' => array(),
-					'border' => array(),
-					'decoding' => array(
-						'value' => array(
-							'async',
-							'auto',
-							'sync',
-						),
-					),
-					'height' => array(),
-					'ismap' => array(),
-					'longdesc' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
-					'sizes' => array(),
-					'src' => array(
-						'alternative_names' => array(
-							'srcset',
-						),
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => true,
-							'protocol' => array(
-								'data',
-								'https',
-							),
-						),
-					),
-					'width' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'noscript',
-					'mandatory_ancestor_suggested_alternative' => 'amp-img',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-img',
-				),
-			),
-		),
-		'input' => array(
-			array(
-				'attr_spec_list' => array(
-					'[accept]' => array(),
-					'[accesskey]' => array(),
-					'[autocomplete]' => array(),
-					'[checked]' => array(),
-					'[disabled]' => array(),
-					'[height]' => array(),
-					'[inputmode]' => array(),
-					'[max]' => array(),
-					'[maxlength]' => array(),
-					'[min]' => array(),
-					'[minlength]' => array(),
-					'[multiple]' => array(),
-					'[pattern]' => array(),
-					'[placeholder]' => array(),
-					'[readonly]' => array(),
-					'[required]' => array(),
-					'[selectiondirection]' => array(),
-					'[size]' => array(),
-					'[spellcheck]' => array(),
-					'[step]' => array(),
-					'[type]' => array(),
-					'[value]' => array(),
-					'[width]' => array(),
-					'accept' => array(),
-					'accesskey' => array(),
-					'autocomplete' => array(),
-					'autofocus' => array(),
-					'checked' => array(),
-					'disabled' => array(),
-					'height' => array(),
-					'inputmode' => array(),
-					'list' => array(),
-					'max' => array(),
-					'maxlength' => array(),
-					'min' => array(),
-					'minlength' => array(),
-					'multiple' => array(),
-					'name' => array(
-						'blacklisted_value_regex' => '(^|\\s)(__amp_\\S*|__count__|__defineGetter__|__defineSetter__|__lookupGetter__|__lookupSetter__|__noSuchMethod__|__parent__|__proto__|__AMP_\\S*|\\$p|\\$proxy|acceptCharset|addEventListener|appendChild|assignedSlot|attachShadow|baseURI|checkValidity|childElementCount|childNodes|classList|className|clientHeight|clientLeft|clientTop|clientWidth|compareDocumentPosition|computedName|computedRole|contentEditable|createShadowRoot|enqueAction|firstChild|firstElementChild|getAnimations|getAttribute|getAttributeNS|getAttributeNode|getAttributeNodeNS|getBoundingClientRect|getClientRects|getDestinationInsertionPoints|getElementsByClassName|getElementsByTagName|getElementsByTagNameNS|getRootNode|hasAttribute|hasAttributeNS|hasAttributes|hasChildNodes|hasPointerCapture|innerHTML|innerText|inputMode|insertAdjacentElement|insertAdjacentHTML|insertAdjacentText|isContentEditable|isDefaultNamespace|isEqualNode|isSameNode|lastChild|lastElementChild|lookupNamespaceURI|namespaceURI|nextElementSibling|nextSibling|nodeName|nodeType|nodeValue|offsetHeight|offsetLeft|offsetParent|offsetTop|offsetWidth|outerHTML|outerText|ownerDocument|parentElement|parentNode|previousElementSibling|previousSibling|querySelector|querySelectorAll|releasePointerCapture|removeAttribute|removeAttributeNS|removeAttributeNode|removeChild|removeEventListener|replaceChild|reportValidity|requestPointerLock|scrollHeight|scrollIntoView|scrollIntoViewIfNeeded|scrollLeft|scrollWidth|setAttribute|setAttributeNS|setAttributeNode|setAttributeNodeNS|setPointerCapture|shadowRoot|styleMap|tabIndex|tagName|textContent|toString|valueOf|(webkit|ms|moz|o)dropzone|(webkit|moz|ms|o)MatchesSelector|(webkit|moz|ms|o)RequestFullScreen|(webkit|moz|ms|o)RequestFullscreen)(\\s|$)',
-					),
-					'no-verify' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'pattern' => array(),
-					'placeholder' => array(),
-					'readonly' => array(),
-					'required' => array(),
-					'selectiondirection' => array(),
-					'size' => array(),
-					'spellcheck' => array(),
-					'step' => array(),
-					'tabindex' => array(),
-					'type' => array(
-						'blacklisted_value_regex' => '(^|\\s)(button|file|image|password|)(\\s|$)',
-					),
-					'value' => array(),
-					'width' => array(),
-				),
-				'tag_spec' => array(
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-form',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'[accept]' => array(),
-					'[accesskey]' => array(),
-					'[autocomplete]' => array(),
-					'[checked]' => array(),
-					'[disabled]' => array(),
-					'[height]' => array(),
-					'[inputmode]' => array(),
-					'[max]' => array(),
-					'[maxlength]' => array(),
-					'[min]' => array(),
-					'[minlength]' => array(),
-					'[multiple]' => array(),
-					'[pattern]' => array(),
-					'[placeholder]' => array(),
-					'[readonly]' => array(),
-					'[required]' => array(),
-					'[selectiondirection]' => array(),
-					'[size]' => array(),
-					'[spellcheck]' => array(),
-					'[step]' => array(),
-					'[value]' => array(),
-					'[width]' => array(),
-					'accept' => array(),
-					'accesskey' => array(),
-					'autocomplete' => array(),
-					'autofocus' => array(),
-					'checked' => array(),
-					'disabled' => array(),
-					'height' => array(),
-					'inputmode' => array(),
-					'list' => array(),
-					'max' => array(),
-					'maxlength' => array(),
-					'min' => array(),
-					'minlength' => array(),
-					'multiple' => array(),
-					'name' => array(
-						'blacklisted_value_regex' => '(^|\\s)(__amp_\\S*|__count__|__defineGetter__|__defineSetter__|__lookupGetter__|__lookupSetter__|__noSuchMethod__|__parent__|__proto__|__AMP_\\S*|\\$p|\\$proxy|acceptCharset|addEventListener|appendChild|assignedSlot|attachShadow|baseURI|checkValidity|childElementCount|childNodes|classList|className|clientHeight|clientLeft|clientTop|clientWidth|compareDocumentPosition|computedName|computedRole|contentEditable|createShadowRoot|enqueAction|firstChild|firstElementChild|getAnimations|getAttribute|getAttributeNS|getAttributeNode|getAttributeNodeNS|getBoundingClientRect|getClientRects|getDestinationInsertionPoints|getElementsByClassName|getElementsByTagName|getElementsByTagNameNS|getRootNode|hasAttribute|hasAttributeNS|hasAttributes|hasChildNodes|hasPointerCapture|innerHTML|innerText|inputMode|insertAdjacentElement|insertAdjacentHTML|insertAdjacentText|isContentEditable|isDefaultNamespace|isEqualNode|isSameNode|lastChild|lastElementChild|lookupNamespaceURI|namespaceURI|nextElementSibling|nextSibling|nodeName|nodeType|nodeValue|offsetHeight|offsetLeft|offsetParent|offsetTop|offsetWidth|outerHTML|outerText|ownerDocument|parentElement|parentNode|previousElementSibling|previousSibling|querySelector|querySelectorAll|releasePointerCapture|removeAttribute|removeAttributeNS|removeAttributeNode|removeChild|removeEventListener|replaceChild|reportValidity|requestPointerLock|scrollHeight|scrollIntoView|scrollIntoViewIfNeeded|scrollLeft|scrollWidth|setAttribute|setAttributeNS|setAttributeNode|setAttributeNodeNS|setPointerCapture|shadowRoot|styleMap|tabIndex|tagName|textContent|toString|valueOf|(webkit|ms|moz|o)dropzone|(webkit|moz|ms|o)MatchesSelector|(webkit|moz|ms|o)RequestFullScreen|(webkit|moz|ms|o)RequestFullscreen)(\\s|$)',
-					),
-					'no-verify' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'pattern' => array(),
-					'placeholder' => array(),
-					'readonly' => array(),
-					'required' => array(),
-					'selectiondirection' => array(),
-					'size' => array(),
-					'spellcheck' => array(),
-					'step' => array(),
-					'tabindex' => array(),
-					'type' => array(
-						'dispatch_key' => 2,
-						'mandatory' => true,
-						'value_casei' => array(
-							'file',
-						),
-					),
-					'value' => array(),
-					'width' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'form [method=post]',
-					'spec_name' => 'INPUT [type=file]',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-form',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'[accept]' => array(),
-					'[accesskey]' => array(),
-					'[autocomplete]' => array(),
-					'[checked]' => array(),
-					'[disabled]' => array(),
-					'[height]' => array(),
-					'[inputmode]' => array(),
-					'[max]' => array(),
-					'[maxlength]' => array(),
-					'[min]' => array(),
-					'[minlength]' => array(),
-					'[multiple]' => array(),
-					'[pattern]' => array(),
-					'[placeholder]' => array(),
-					'[readonly]' => array(),
-					'[required]' => array(),
-					'[selectiondirection]' => array(),
-					'[size]' => array(),
-					'[spellcheck]' => array(),
-					'[step]' => array(),
-					'[value]' => array(),
-					'[width]' => array(),
-					'accept' => array(),
-					'accesskey' => array(),
-					'autocomplete' => array(),
-					'autofocus' => array(),
-					'checked' => array(),
-					'disabled' => array(),
-					'height' => array(),
-					'inputmode' => array(),
-					'list' => array(),
-					'max' => array(),
-					'maxlength' => array(),
-					'min' => array(),
-					'minlength' => array(),
-					'multiple' => array(),
-					'name' => array(
-						'blacklisted_value_regex' => '(^|\\s)(__amp_\\S*|__count__|__defineGetter__|__defineSetter__|__lookupGetter__|__lookupSetter__|__noSuchMethod__|__parent__|__proto__|__AMP_\\S*|\\$p|\\$proxy|acceptCharset|addEventListener|appendChild|assignedSlot|attachShadow|baseURI|checkValidity|childElementCount|childNodes|classList|className|clientHeight|clientLeft|clientTop|clientWidth|compareDocumentPosition|computedName|computedRole|contentEditable|createShadowRoot|enqueAction|firstChild|firstElementChild|getAnimations|getAttribute|getAttributeNS|getAttributeNode|getAttributeNodeNS|getBoundingClientRect|getClientRects|getDestinationInsertionPoints|getElementsByClassName|getElementsByTagName|getElementsByTagNameNS|getRootNode|hasAttribute|hasAttributeNS|hasAttributes|hasChildNodes|hasPointerCapture|innerHTML|innerText|inputMode|insertAdjacentElement|insertAdjacentHTML|insertAdjacentText|isContentEditable|isDefaultNamespace|isEqualNode|isSameNode|lastChild|lastElementChild|lookupNamespaceURI|namespaceURI|nextElementSibling|nextSibling|nodeName|nodeType|nodeValue|offsetHeight|offsetLeft|offsetParent|offsetTop|offsetWidth|outerHTML|outerText|ownerDocument|parentElement|parentNode|previousElementSibling|previousSibling|querySelector|querySelectorAll|releasePointerCapture|removeAttribute|removeAttributeNS|removeAttributeNode|removeChild|removeEventListener|replaceChild|reportValidity|requestPointerLock|scrollHeight|scrollIntoView|scrollIntoViewIfNeeded|scrollLeft|scrollWidth|setAttribute|setAttributeNS|setAttributeNode|setAttributeNodeNS|setPointerCapture|shadowRoot|styleMap|tabIndex|tagName|textContent|toString|valueOf|(webkit|ms|moz|o)dropzone|(webkit|moz|ms|o)MatchesSelector|(webkit|moz|ms|o)RequestFullScreen|(webkit|moz|ms|o)RequestFullscreen)(\\s|$)',
-					),
-					'pattern' => array(),
-					'placeholder' => array(),
-					'readonly' => array(),
-					'required' => array(),
-					'selectiondirection' => array(),
-					'size' => array(),
-					'spellcheck' => array(),
-					'step' => array(),
-					'tabindex' => array(),
-					'type' => array(
-						'dispatch_key' => 2,
-						'mandatory' => true,
-						'value_casei' => array(
-							'password',
-						),
-					),
-					'value' => array(),
-					'width' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'form [method=post]',
-					'spec_name' => 'INPUT [type=password]',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-form',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'[accept]' => array(),
-					'[accesskey]' => array(),
-					'[autocomplete]' => array(),
-					'[checked]' => array(),
-					'[disabled]' => array(),
-					'[height]' => array(),
-					'[inputmode]' => array(),
-					'[max]' => array(),
-					'[maxlength]' => array(),
-					'[min]' => array(),
-					'[minlength]' => array(),
-					'[multiple]' => array(),
-					'[pattern]' => array(),
-					'[placeholder]' => array(),
-					'[readonly]' => array(),
-					'[required]' => array(),
-					'[selectiondirection]' => array(),
-					'[size]' => array(),
-					'[spellcheck]' => array(),
-					'[step]' => array(),
-					'[type]' => array(),
-					'[value]' => array(),
-					'[width]' => array(),
-					'accept' => array(),
-					'accesskey' => array(),
-					'autocomplete' => array(),
-					'autofocus' => array(),
-					'checked' => array(),
-					'disabled' => array(),
-					'height' => array(),
-					'inputmode' => array(),
-					'list' => array(),
-					'mask' => array(
-						'dispatch_key' => 1,
-						'mandatory' => true,
-					),
-					'mask-output' => array(),
-					'max' => array(),
-					'maxlength' => array(),
-					'min' => array(),
-					'minlength' => array(),
-					'multiple' => array(),
-					'name' => array(
-						'blacklisted_value_regex' => '(^|\\s)(__amp_\\S*|__count__|__defineGetter__|__defineSetter__|__lookupGetter__|__lookupSetter__|__noSuchMethod__|__parent__|__proto__|__AMP_\\S*|\\$p|\\$proxy|acceptCharset|addEventListener|appendChild|assignedSlot|attachShadow|baseURI|checkValidity|childElementCount|childNodes|classList|className|clientHeight|clientLeft|clientTop|clientWidth|compareDocumentPosition|computedName|computedRole|contentEditable|createShadowRoot|enqueAction|firstChild|firstElementChild|getAnimations|getAttribute|getAttributeNS|getAttributeNode|getAttributeNodeNS|getBoundingClientRect|getClientRects|getDestinationInsertionPoints|getElementsByClassName|getElementsByTagName|getElementsByTagNameNS|getRootNode|hasAttribute|hasAttributeNS|hasAttributes|hasChildNodes|hasPointerCapture|innerHTML|innerText|inputMode|insertAdjacentElement|insertAdjacentHTML|insertAdjacentText|isContentEditable|isDefaultNamespace|isEqualNode|isSameNode|lastChild|lastElementChild|lookupNamespaceURI|namespaceURI|nextElementSibling|nextSibling|nodeName|nodeType|nodeValue|offsetHeight|offsetLeft|offsetParent|offsetTop|offsetWidth|outerHTML|outerText|ownerDocument|parentElement|parentNode|previousElementSibling|previousSibling|querySelector|querySelectorAll|releasePointerCapture|removeAttribute|removeAttributeNS|removeAttributeNode|removeChild|removeEventListener|replaceChild|reportValidity|requestPointerLock|scrollHeight|scrollIntoView|scrollIntoViewIfNeeded|scrollLeft|scrollWidth|setAttribute|setAttributeNS|setAttributeNode|setAttributeNodeNS|setPointerCapture|shadowRoot|styleMap|tabIndex|tagName|textContent|toString|valueOf|(webkit|ms|moz|o)dropzone|(webkit|moz|ms|o)MatchesSelector|(webkit|moz|ms|o)RequestFullScreen|(webkit|moz|ms|o)RequestFullscreen)(\\s|$)',
-					),
-					'pattern' => array(),
-					'placeholder' => array(),
-					'readonly' => array(),
-					'required' => array(),
-					'selectiondirection' => array(),
-					'size' => array(),
-					'spellcheck' => array(),
-					'step' => array(),
-					'tabindex' => array(),
-					'type' => array(
-						'value' => array(
-							'text',
-							'tel',
-							'search',
-						),
-					),
-					'value' => array(),
-					'width' => array(),
-				),
-				'tag_spec' => array(
-					'requires_extension' => array(
-						'amp-inputmask',
-					),
-					'spec_name' => 'input [mask]',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-inputmask',
-				),
-			),
-		),
-		'ins' => array(
-			array(
-				'attr_spec_list' => array(
-					'cite' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_empty' => true,
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
-					'datetime' => array(),
-				),
-				'tag_spec' => array(),
-			),
-		),
-		'kbd' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'label' => array(
-			array(
-				'attr_spec_list' => array(
-					'for' => array(),
-				),
-				'tag_spec' => array(
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-form',
-				),
-			),
-		),
-		'legend' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'li' => array(
-			array(
-				'attr_spec_list' => array(
-					'value' => array(
-						'value_regex' => '[0-9]*',
-					),
-				),
-				'tag_spec' => array(),
-			),
-		),
-		'line' => array(
-			array(
-				'attr_spec_list' => array(
-					'alignment-baseline' => array(),
-					'baseline-shift' => array(),
-					'clip' => array(),
-					'clip-path' => array(),
-					'clip-rule' => array(),
-					'color' => array(),
-					'color-interpolation' => array(),
-					'color-interpolation-filters' => array(),
-					'color-profile' => array(),
-					'color-rendering' => array(),
-					'cursor' => array(),
-					'direction' => array(),
-					'display' => array(),
-					'dominant-baseline' => array(),
-					'enable-background' => array(),
-					'externalresourcesrequired' => array(),
-					'fill' => array(),
-					'fill-opacity' => array(),
-					'fill-rule' => array(),
-					'filter' => array(),
-					'flood-color' => array(),
-					'flood-opacity' => array(),
-					'focusable' => array(),
-					'font-family' => array(),
-					'font-size' => array(),
-					'font-size-adjust' => array(),
-					'font-stretch' => array(),
-					'font-style' => array(),
-					'font-variant' => array(),
-					'font-weight' => array(),
-					'glyph-orientation-horizontal' => array(),
-					'glyph-orientation-vertical' => array(),
-					'image-rendering' => array(),
-					'kerning' => array(),
-					'letter-spacing' => array(),
-					'lighting-color' => array(),
-					'marker-end' => array(),
-					'marker-mid' => array(),
-					'marker-start' => array(),
-					'mask' => array(),
-					'opacity' => array(),
-					'overflow' => array(),
-					'pointer-events' => array(),
-					'requiredextensions' => array(),
-					'requiredfeatures' => array(),
-					'shape-rendering' => array(),
-					'sketch:type' => array(),
-					'stop-color' => array(),
-					'stop-opacity' => array(),
-					'stroke' => array(),
-					'stroke-dasharray' => array(),
-					'stroke-dashoffset' => array(),
-					'stroke-linecap' => array(),
-					'stroke-linejoin' => array(),
-					'stroke-miterlimit' => array(),
-					'stroke-opacity' => array(),
-					'stroke-width' => array(),
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'systemlanguage' => array(),
-					'text-anchor' => array(),
-					'text-decoration' => array(),
-					'text-rendering' => array(),
-					'transform' => array(),
-					'unicode-bidi' => array(),
-					'vector-effect' => array(),
-					'visibility' => array(),
-					'word-spacing' => array(),
-					'writing-mode' => array(),
-					'x1' => array(),
-					'x2' => array(),
-					'xml:lang' => array(),
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-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
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-					'fill-rule' => array(),
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-					'font-family' => array(),
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-					'font-weight' => array(),
-					'glyph-orientation-horizontal' => array(),
-					'glyph-orientation-vertical' => array(),
-					'gradienttransform' => array(),
-					'gradientunits' => array(),
-					'image-rendering' => array(),
-					'kerning' => array(),
-					'letter-spacing' => array(),
-					'lighting-color' => array(),
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-					'marker-mid' => array(),
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-					'mask' => array(),
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-					'overflow' => array(),
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-					'spreadmethod' => array(),
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-					),
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-					'text-decoration' => array(),
-					'text-rendering' => array(),
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-					'xlink:arcrole' => array(),
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-						),
-						'value_url' => array(
-							'allow_empty' => false,
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
-					'xlink:role' => array(),
-					'xlink:show' => array(),
-					'xlink:title' => array(),
-					'xlink:type' => array(),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-					'y1' => array(),
-					'y2' => array(),
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-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'link' => array(
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-				'attr_spec_list' => array(
-					'charset' => array(
-						'value_casei' => array(
-							'utf-8',
-						),
-					),
-					'color' => array(),
-					'crossorigin' => array(),
-					'href' => array(),
-					'hreflang' => array(),
-					'media' => array(),
-					'rel' => array(
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-						'mandatory' => true,
-					),
-					'sizes' => array(),
-					'target' => array(),
-					'type' => array(),
-				),
-				'tag_spec' => array(
-					'disallowed_ancestor' => array(
-						'template',
-					),
-					'spec_name' => 'link rel=',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#html-tags',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'charset' => array(
-						'value_casei' => array(
-							'utf-8',
-						),
-					),
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-					'crossorigin' => array(),
-					'href' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
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-					'media' => array(),
-					'rel' => array(
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-						'value_casei' => array(
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-				'tag_spec' => array(
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-					'mandatory_parent' => 'head',
-					'spec_name' => 'link rel=canonical',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#required-markup',
-					'unique' => true,
-				),
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-			array(
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-					'crossorigin' => array(),
-					'href' => array(
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-						'mandatory' => true,
-						'value_url' => array(
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-								'https',
-							),
-						),
-					),
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-					'media' => array(),
-					'rel' => array(
-						'dispatch_key' => 2,
-						'mandatory' => true,
-						'value_casei' => array(
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-					),
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-					'target' => array(),
-					'type' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'head',
-					'spec_name' => 'link rel=manifest',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#html-tags',
-				),
-			),
-			array(
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-					'charset' => array(
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-							'utf-8',
-						),
-					),
-					'color' => array(),
-					'crossorigin' => array(),
-					'href' => array(),
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-					'media' => array(),
-					'rel' => array(
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-						'mandatory' => true,
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-				'tag_spec' => array(
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-						'template',
-					),
-					'spec_name' => 'link rel=preload',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#html-tags',
-				),
-			),
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-					'async' => array(),
-					'crossorigin' => array(),
-					'href' => array(
-						'mandatory' => true,
-						'value_regex' => 'https://cdn\\.materialdesignicons\\.com/([0-9]+\\.?)+/css/materialdesignicons\\.min\\.css|https://cloud\\.typography\\.com/[0-9]*/[0-9]*/css/fonts\\.css|https://fast\\.fonts\\.net/.*|https://fonts\\.googleapis\\.com/css\\?.*|https://fonts\\.googleapis\\.com/icon\\?.*|https://fonts\\.googleapis\\.com/earlyaccess/.*\\.css|https://maxcdn\\.bootstrapcdn\\.com/font-awesome/([0-9]+\\.?)+/css/font-awesome\\.min\\.css(\\?.*)?|https://(use|pro)\\.fontawesome\\.com/releases/v([0-9]+\\.?)+/css/(all|brands|solid|regular|light|fontawesome)\\.css|https://(use|pro)\\.fontawesome\\.com/[0-9a-zA-Z]+\\.css|https://use\\.typekit\\.net/[\\w\\p{L}\\p{N}_]+\\.css',
-					),
-					'integrity' => array(),
-					'media' => array(),
-					'rel' => array(
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-						'mandatory' => true,
-						'value_casei' => array(
-							'stylesheet',
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-							'text/css',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'head',
-					'spec_name' => 'link rel=stylesheet for fonts',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#custom-fonts',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
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-						'value_casei' => array(
-							'utf-8',
-						),
-					),
-					'color' => array(),
-					'crossorigin' => array(),
-					'href' => array(
-						'mandatory' => true,
-					),
-					'hreflang' => array(),
-					'itemprop' => array(
-						'dispatch_key' => 2,
-						'mandatory' => true,
-						'value_casei' => array(
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-					'sizes' => array(),
-					'target' => array(),
-					'type' => array(),
-				),
-				'tag_spec' => array(
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-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#html-tags',
-				),
-			),
-			array(
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-					),
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-					'itemprop' => array(
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-					),
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-					'target' => array(),
-					'type' => array(),
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-				),
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-					'media' => array(),
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-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#html-tags',
-				),
-			),
-		),
-		'listing' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'main' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'mark' => array(
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-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
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-					'baseline-shift' => array(),
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-					'color-profile' => array(),
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-					'enable-background' => array(),
-					'externalresourcesrequired' => array(),
-					'fill' => array(),
-					'fill-opacity' => array(),
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-					'filter' => array(),
-					'flood-color' => array(),
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-					'font-family' => array(),
-					'font-size' => array(),
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-					'font-style' => array(),
-					'font-variant' => array(),
-					'font-weight' => array(),
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-					'glyph-orientation-vertical' => array(),
-					'image-rendering' => array(),
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-					'letter-spacing' => array(),
-					'lighting-color' => array(),
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-					'opacity' => array(),
-					'orient' => array(),
-					'overflow' => array(),
-					'pointer-events' => array(),
-					'preserveaspectratio' => array(),
-					'refx' => array(),
-					'refy' => array(),
-					'shape-rendering' => array(),
-					'stop-color' => array(),
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-					'stroke-width' => array(),
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-					),
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-					'text-decoration' => array(),
-					'text-rendering' => array(),
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-					'unicode-bidi' => array(),
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-					'viewbox' => array(),
-					'visibility' => array(),
-					'word-spacing' => array(),
-					'writing-mode' => array(),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
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-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
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-					'clip' => array(),
-					'clip-path' => array(),
-					'clip-rule' => array(),
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-					'color-profile' => array(),
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-					'direction' => array(),
-					'display' => array(),
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-					'enable-background' => array(),
-					'externalresourcesrequired' => array(),
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-					'fill-rule' => array(),
-					'filter' => array(),
-					'flood-color' => array(),
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-					'focusable' => array(),
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-					'font-size' => array(),
-					'font-size-adjust' => array(),
-					'font-stretch' => array(),
-					'font-style' => array(),
-					'font-variant' => array(),
-					'font-weight' => array(),
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-					'glyph-orientation-vertical' => array(),
-					'height' => array(),
-					'image-rendering' => array(),
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-					'letter-spacing' => array(),
-					'lighting-color' => array(),
-					'marker-end' => array(),
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-					'mask' => array(),
-					'maskcontentunits' => array(),
-					'maskunits' => array(),
-					'opacity' => array(),
-					'overflow' => array(),
-					'pointer-events' => array(),
-					'requiredextensions' => array(),
-					'requiredfeatures' => array(),
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-					'stop-opacity' => array(),
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-					'stroke-width' => array(),
-					'style' => array(
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-					'text-anchor' => array(),
-					'text-decoration' => array(),
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-					'writing-mode' => array(),
-					'x' => array(),
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-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-					'y' => array(),
-				),
-				'tag_spec' => array(
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-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
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-					'charset' => array(
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-					'mandatory_parent' => 'head',
-					'spec_name' => 'meta charset=utf-8',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#required-markup',
-					'unique' => true,
-				),
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-			array(
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-						'value_properties' => array(
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-							'initial-scale' => array(),
-							'maximum-scale' => array(),
-							'minimum-scale' => array(),
-							'shrink-to-fit' => array(),
-							'user-scalable' => array(),
-							'viewport-fit' => array(),
-							'width' => array(
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-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#required-markup',
-					'unique' => true,
-				),
-			),
-			array(
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-						'value_properties' => array(
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-								'value' => '1',
-							),
-							'ie' => array(
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-							),
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-						'mandatory' => true,
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-						),
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-					'mandatory_ancestor' => 'head',
-					'spec_name' => 'meta http-equiv=X-UA-Compatible',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#html-tags',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'content' => array(
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-						'value_regex' => '.*app-id=.*',
-					),
-					'name' => array(
-						'dispatch_key' => 2,
-						'mandatory' => true,
-						'value_casei' => array(
-							'apple-itunes-app',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'head',
-					'spec_name' => 'meta name=apple-itunes-app',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#html-tags',
-				),
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-					'spec_name' => 'meta name=amp-experiments-opt-in',
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-						'value_url' => array(
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-							),
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-						),
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-					'spec_name' => 'meta name=amp-3p-iframe-src',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-ad',
-				),
-			),
-			array(
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-					),
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-						'mandatory' => true,
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-							'amp-experiment-token',
-						),
-					),
-				),
-				'tag_spec' => array(
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-					'spec_name' => 'meta name=amp-experiment-token',
-				),
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-					),
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-						'mandatory' => true,
-						'value_casei' => array(
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-						),
-					),
-				),
-				'tag_spec' => array(
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-					'spec_name' => 'meta name=amp-link-variable-allowed-origin',
-				),
-			),
-			array(
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-					),
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-						'mandatory' => true,
-						'value_casei' => array(
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-						),
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'head',
-					'spec_name' => 'meta name=amp-google-clientid-id-api',
-				),
-			),
-			array(
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-						'mandatory' => true,
-						'value_casei' => array(
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-						),
-					),
-				),
-				'tag_spec' => array(
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-					'spec_name' => 'meta name=amp-ad-doubleclick-sra',
-				),
-			),
-			array(
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-					'content' => array(),
-					'itemprop' => array(),
-					'name' => array(
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-					),
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-					'scheme' => array(),
-				),
-				'tag_spec' => array(
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-				),
-			),
-			array(
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-					'content' => array(
-						'mandatory' => true,
-						'value_casei' => array(
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-						),
-					),
-					'http-equiv' => array(
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-						'mandatory' => true,
-						'value_casei' => array(
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-						),
-					),
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-					'spec_name' => 'meta http-equiv=Content-Type',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#html-tags',
-				),
-			),
-			array(
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-					),
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-						),
-					),
-				),
-				'tag_spec' => array(
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-					'spec_name' => 'meta http-equiv=content-language',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#html-tags',
-				),
-			),
-			array(
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-					),
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-						),
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'head',
-					'spec_name' => 'meta http-equiv=pics-label',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#html-tags',
-				),
-			),
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-					),
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-					'spec_name' => 'meta http-equiv=imagetoolbar',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#html-tags',
-				),
-			),
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-						'value_casei' => array(
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-						),
-					),
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-						'mandatory' => true,
-						'value_casei' => array(
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-						),
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-				'tag_spec' => array(
-					'mandatory_ancestor' => 'head',
-					'spec_name' => 'meta http-equiv=Content-Style-Type',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#html-tags',
-				),
-			),
-			array(
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-						'value_casei' => array(
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-						),
-					),
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-						'mandatory' => true,
-						'value_casei' => array(
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-					'mandatory_ancestor' => 'head',
-					'spec_name' => 'meta http-equiv=Content-Script-Type',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#html-tags',
-				),
-			),
-			array(
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-						'mandatory' => true,
-					),
-					'http-equiv' => array(
-						'dispatch_key' => 2,
-						'mandatory' => true,
-						'value_casei' => array(
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-					'mandatory_ancestor' => 'head',
-					'spec_name' => 'meta http-equiv=origin-trial',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#html-tags',
-				),
-			),
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-					),
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-						'mandatory' => true,
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-					'mandatory_ancestor' => 'head',
-					'spec_name' => 'meta http-equiv=resource-type',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#html-tags',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'content' => array(
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-						'value_casei' => array(
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-						'mandatory' => true,
-						'value_casei' => array(
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-					'spec_name' => 'meta http-equiv=x-dns-prefetch-control',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#html-tags',
-				),
-			),
-			array(
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-					),
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-						'mandatory' => true,
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-						),
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'head',
-					'spec_name' => 'meta name=amp-ad-enable-refresh',
-				),
-			),
-			array(
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-						),
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'head',
-					'spec_name' => 'meta name=amp-to-amp-navigation',
-					'unique' => true,
-				),
-			),
-		),
-		'metadata' => array(
-			array(
-				'attr_spec_list' => array(
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'svg',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'meter' => array(
-			array(
-				'attr_spec_list' => array(
-					'high' => array(),
-					'low' => array(),
-					'max' => array(),
-					'min' => array(),
-					'optimum' => array(),
-					'value' => array(),
-				),
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-			),
-		),
-		'multicol' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'nav' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-			array(
-				'attr_spec_list' => array(
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-						'mandatory' => true,
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-					'toolbar-target' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'amp-sidebar',
-					'spec_name' => 'amp-sidebar > nav',
-				),
-			),
-		),
-		'nextid' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'nobr' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'noscript' => array(
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-				'attr_spec_list' => array(),
-				'tag_spec' => array(
-					'mandatory' => true,
-					'mandatory_parent' => 'head',
-					'spec_name' => 'noscript enclosure for boilerplate',
-					'spec_url' => 'https://github.com/ampproject/amphtml/blob/master/spec/amp-boilerplate.md',
-					'unique' => true,
-				),
-			),
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(
-					'disallowed_ancestor' => array(
-						'noscript',
-					),
-					'mandatory_ancestor' => 'body',
-				),
-			),
-		),
-		'o:p' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'ol' => array(
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-						),
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-					),
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-						'value_regex' => '[1AaIi]',
-					),
-				),
-				'tag_spec' => array(),
-			),
-		),
-		'optgroup' => array(
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-				'attr_spec_list' => array(
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-					'[label]' => array(),
-					'disabled' => array(),
-					'label' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'select',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-form',
-				),
-			),
-		),
-		'option' => array(
-			array(
-				'attr_spec_list' => array(
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-					'[label]' => array(),
-					'[selected]' => array(),
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-					'disabled' => array(),
-					'label' => array(),
-					'selected' => array(),
-					'value' => array(),
-				),
-				'tag_spec' => array(
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-form',
-				),
-			),
-		),
-		'output' => array(
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-					'form' => array(),
-					'name' => array(
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-					),
-				),
-				'tag_spec' => array(),
-			),
-		),
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-				'tag_spec' => array(),
-			),
-		),
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-					'font-style' => array(),
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-					'requiredextensions' => array(),
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-					'text-anchor' => array(),
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-					'xml:lang' => array(),
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-				'tag_spec' => array(
-					'mandatory_ancestor' => 'svg',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'pattern' => array(
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-					'height' => array(),
-					'image-rendering' => array(),
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-					'letter-spacing' => array(),
-					'lighting-color' => array(),
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-					'patterncontentunits' => array(),
-					'patterntransform' => array(),
-					'patternunits' => array(),
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-					'requiredextensions' => array(),
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-							'protocol' => array(
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-								'https',
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-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-img',
-				),
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-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
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-							'protocol' => array(
-								'http',
-								'https',
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-							'protocol' => array(
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-					'spec_name' => 'amp-subscriptions extension .json script',
-					'unique' => true,
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'async' => array(
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'nonce' => array(),
-					'type' => array(
-						'value_casei' => array(
-							'text/javascript',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'extension_spec' => array(
-						'name' => 'amp-subscriptions-google',
-						'requires_usage' => 3,
-						'version' => array(
-							'0.1',
-							'latest',
-						),
-					),
-					'requires_extension' => array(
-						'amp-subscriptions',
-					),
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'async' => array(
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'nonce' => array(),
-					'type' => array(
-						'value_casei' => array(
-							'text/javascript',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'extension_spec' => array(
-						'name' => 'amp-timeago',
-						'version' => array(
-							'0.1',
-							'latest',
-						),
-					),
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'async' => array(
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'nonce' => array(),
-					'type' => array(
-						'value_casei' => array(
-							'text/javascript',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'extension_spec' => array(
-						'deprecated_allow_duplicates' => true,
-						'name' => 'amp-twitter',
-						'requires_usage' => 2,
-						'version' => array(
-							'0.1',
-							'latest',
-						),
-					),
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'async' => array(
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'nonce' => array(),
-					'type' => array(
-						'value_casei' => array(
-							'text/javascript',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'extension_spec' => array(
-						'deprecated_allow_duplicates' => true,
-						'name' => 'amp-user-notification',
-						'requires_usage' => 2,
-						'version' => array(
-							'0.1',
-							'latest',
-						),
-					),
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'async' => array(
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'nonce' => array(),
-					'type' => array(
-						'value_casei' => array(
-							'text/javascript',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'extension_spec' => array(
-						'name' => 'amp-video-docking',
-						'requires_usage' => 3,
-						'version' => array(
-							'0.1',
-							'latest',
-						),
-					),
-					'requires_extension' => array(
-						'amp-video',
-					),
-					'spec_name' => 'amp-video-docking for amp-video',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'async' => array(
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'nonce' => array(),
-					'type' => array(
-						'value_casei' => array(
-							'text/javascript',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'extension_spec' => array(
-						'name' => 'amp-video-iframe',
-						'version' => array(
-							'0.1',
-							'latest',
-						),
-					),
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'async' => array(
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'nonce' => array(),
-					'type' => array(
-						'value_casei' => array(
-							'text/javascript',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'extension_spec' => array(
-						'name' => 'amp-video',
-						'requires_usage' => 3,
-						'version' => array(
-							'0.1',
-							'latest',
-						),
-					),
-					'spec_name' => 'amp-video extension .js script',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'async' => array(
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'nonce' => array(),
-					'type' => array(
-						'value_casei' => array(
-							'text/javascript',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'extension_spec' => array(
-						'deprecated_allow_duplicates' => true,
-						'name' => 'amp-vimeo',
-						'requires_usage' => 2,
-						'version' => array(
-							'0.1',
-							'latest',
-						),
-					),
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'async' => array(
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'nonce' => array(),
-					'type' => array(
-						'value_casei' => array(
-							'text/javascript',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'extension_spec' => array(
-						'deprecated_allow_duplicates' => true,
-						'name' => 'amp-vine',
-						'requires_usage' => 2,
-						'version' => array(
-							'0.1',
-							'latest',
-						),
-					),
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'async' => array(
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'nonce' => array(),
-					'type' => array(
-						'value_casei' => array(
-							'text/javascript',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'extension_spec' => array(
-						'name' => 'amp-viqeo-player',
-						'version' => array(
-							'0.1',
-							'latest',
-						),
-					),
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'async' => array(
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'nonce' => array(),
-					'type' => array(
-						'value_casei' => array(
-							'text/javascript',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'extension_spec' => array(
-						'name' => 'amp-vk',
-						'version' => array(
-							'0.1',
-							'latest',
-						),
-					),
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'async' => array(
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'nonce' => array(),
-					'type' => array(
-						'value_casei' => array(
-							'text/javascript',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'extension_spec' => array(
-						'name' => 'amp-web-push',
-						'version' => array(
-							'0.1',
-							'latest',
-						),
-					),
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'async' => array(
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'nonce' => array(),
-					'type' => array(
-						'value_casei' => array(
-							'text/javascript',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'extension_spec' => array(
-						'name' => 'amp-wistia-player',
-						'version' => array(
-							'0.1',
-							'latest',
-						),
-					),
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'async' => array(
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'nonce' => array(),
-					'type' => array(
-						'value_casei' => array(
-							'text/javascript',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'extension_spec' => array(
-						'name' => 'amp-yotpo',
-						'version' => array(
-							'0.1',
-							'latest',
-						),
-					),
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-yotpo',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'async' => array(
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'nonce' => array(),
-					'type' => array(
-						'value_casei' => array(
-							'text/javascript',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'extension_spec' => array(
-						'deprecated_allow_duplicates' => true,
-						'name' => 'amp-youtube',
-						'requires_usage' => 2,
-						'version' => array(
-							'0.1',
-							'latest',
-						),
-					),
-				),
-			),
-		),
-		'section' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(
-					'disallowed_ancestor' => array(
-						'amp-accordion',
-					),
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'expanded' => array(
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'amp-accordion',
-					'spec_name' => 'amp-accordion > section',
-				),
-			),
-		),
-		'select' => array(
-			array(
-				'attr_spec_list' => array(
-					'[autofocus]' => array(),
-					'[disabled]' => array(),
-					'[multiple]' => array(),
-					'[required]' => array(),
-					'[size]' => array(),
-					'autofocus' => array(),
-					'disabled' => array(),
-					'multiple' => array(),
-					'name' => array(
-						'blacklisted_value_regex' => '(^|\\s)(__amp_\\S*|__count__|__defineGetter__|__defineSetter__|__lookupGetter__|__lookupSetter__|__noSuchMethod__|__parent__|__proto__|__AMP_\\S*|\\$p|\\$proxy|acceptCharset|addEventListener|appendChild|assignedSlot|attachShadow|baseURI|checkValidity|childElementCount|childNodes|classList|className|clientHeight|clientLeft|clientTop|clientWidth|compareDocumentPosition|computedName|computedRole|contentEditable|createShadowRoot|enqueAction|firstChild|firstElementChild|getAnimations|getAttribute|getAttributeNS|getAttributeNode|getAttributeNodeNS|getBoundingClientRect|getClientRects|getDestinationInsertionPoints|getElementsByClassName|getElementsByTagName|getElementsByTagNameNS|getRootNode|hasAttribute|hasAttributeNS|hasAttributes|hasChildNodes|hasPointerCapture|innerHTML|innerText|inputMode|insertAdjacentElement|insertAdjacentHTML|insertAdjacentText|isContentEditable|isDefaultNamespace|isEqualNode|isSameNode|lastChild|lastElementChild|lookupNamespaceURI|namespaceURI|nextElementSibling|nextSibling|nodeName|nodeType|nodeValue|offsetHeight|offsetLeft|offsetParent|offsetTop|offsetWidth|outerHTML|outerText|ownerDocument|parentElement|parentNode|previousElementSibling|previousSibling|querySelector|querySelectorAll|releasePointerCapture|removeAttribute|removeAttributeNS|removeAttributeNode|removeChild|removeEventListener|replaceChild|reportValidity|requestPointerLock|scrollHeight|scrollIntoView|scrollIntoViewIfNeeded|scrollLeft|scrollWidth|setAttribute|setAttributeNS|setAttributeNode|setAttributeNodeNS|setPointerCapture|shadowRoot|styleMap|tabIndex|tagName|textContent|toString|valueOf|(webkit|ms|moz|o)dropzone|(webkit|moz|ms|o)MatchesSelector|(webkit|moz|ms|o)RequestFullScreen|(webkit|moz|ms|o)RequestFullscreen)(\\s|$)',
-					),
-					'no-verify' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'required' => array(),
-					'size' => array(),
-				),
-				'tag_spec' => array(
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-form',
-				),
-			),
-		),
-		'slot' => array(
-			array(
-				'attr_spec_list' => array(
-					'name' => array(),
-				),
-				'tag_spec' => array(),
-			),
-		),
-		'small' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'solidcolor' => array(
-			array(
-				'attr_spec_list' => array(
-					'alignment-baseline' => array(),
-					'baseline-shift' => array(),
-					'clip' => array(),
-					'clip-path' => array(),
-					'clip-rule' => array(),
-					'color' => array(),
-					'color-interpolation' => array(),
-					'color-interpolation-filters' => array(),
-					'color-profile' => array(),
-					'color-rendering' => array(),
-					'cursor' => array(),
-					'direction' => array(),
-					'display' => array(),
-					'dominant-baseline' => array(),
-					'enable-background' => array(),
-					'fill' => array(),
-					'fill-opacity' => array(),
-					'fill-rule' => array(),
-					'filter' => array(),
-					'flood-color' => array(),
-					'flood-opacity' => array(),
-					'focusable' => array(),
-					'font-family' => array(),
-					'font-size' => array(),
-					'font-size-adjust' => array(),
-					'font-stretch' => array(),
-					'font-style' => array(),
-					'font-variant' => array(),
-					'font-weight' => array(),
-					'glyph-orientation-horizontal' => array(),
-					'glyph-orientation-vertical' => array(),
-					'image-rendering' => array(),
-					'kerning' => array(),
-					'letter-spacing' => array(),
-					'lighting-color' => array(),
-					'marker-end' => array(),
-					'marker-mid' => array(),
-					'marker-start' => array(),
-					'mask' => array(),
-					'opacity' => array(),
-					'overflow' => array(),
-					'pointer-events' => array(),
-					'shape-rendering' => array(),
-					'solid-color' => array(),
-					'solid-opacity' => array(),
-					'stop-color' => array(),
-					'stop-opacity' => array(),
-					'stroke' => array(),
-					'stroke-dasharray' => array(),
-					'stroke-dashoffset' => array(),
-					'stroke-linecap' => array(),
-					'stroke-linejoin' => array(),
-					'stroke-miterlimit' => array(),
-					'stroke-opacity' => array(),
-					'stroke-width' => array(),
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'text-anchor' => array(),
-					'text-decoration' => array(),
-					'text-rendering' => array(),
-					'unicode-bidi' => array(),
-					'vector-effect' => array(),
-					'visibility' => array(),
-					'word-spacing' => array(),
-					'writing-mode' => array(),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'svg',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'source' => array(
-			array(
-				'attr_spec_list' => array(
-					'media' => array(),
-					'sizes' => array(),
-					'srcset' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => true,
-							'protocol' => array(
-								'data',
-								'http',
-								'https',
-							),
-						),
-					),
-					'type' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'picture',
-					'spec_name' => 'picture > source',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-img',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'[src]' => array(),
-					'[type]' => array(),
-					'media' => array(),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => true,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'type' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'amp-video',
-					'spec_name' => 'amp-video > source',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-video',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'[src]' => array(),
-					'[type]' => array(),
-					'media' => array(),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => true,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'type' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'amp-audio',
-					'spec_name' => 'amp-audio > source',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-audio',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'media' => array(),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => true,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'type' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'audio',
-					'spec_name' => 'audio > source',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-audio',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'media' => array(),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => true,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'type' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'video',
-					'spec_name' => 'video > source',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-video',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'[src]' => array(),
-					'[type]' => array(),
-					'media' => array(),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => true,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'type' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'amp-ima-video',
-					'requires_extension' => array(
-						'amp-ima-video',
-					),
-					'spec_name' => 'amp-ima-video > source',
-				),
-			),
-		),
-		'spacer' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'span' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'stop' => array(
-			array(
-				'attr_spec_list' => array(
-					'offset' => array(),
-					'stop-color' => array(),
-					'stop-opacity' => array(),
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'lineargradient',
-					'spec_name' => 'lineargradient > stop',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'offset' => array(),
-					'stop-color' => array(),
-					'stop-opacity' => array(),
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'radialgradient',
-					'spec_name' => 'radialgradient > stop',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'strike' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'strong' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'style' => array(
-			array(
-				'attr_spec_list' => array(
-					'amp-custom' => array(
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'nonce' => array(),
-					'type' => array(
-						'value_casei' => array(
-							'text/css',
-						),
-					),
-				),
-				'cdata' => array(
-					'blacklisted_cdata_regex' => array(
-						'error_message' => 'CSS !important',
-						'regex' => '!important',
-					),
-					'css_spec' => array(
-						'allowed_at_rules' => array(
-							'font-face',
-							'keyframes',
-							'media',
-							'page',
-							'supports',
-						),
-						'declaration' => array(),
-						'font_url_spec' => array(
-							'allow_empty' => true,
-							'protocol' => array(
-								'https',
-								'http',
-								'data',
-							),
-						),
-						'image_url_spec' => array(
-							'allow_empty' => true,
-							'protocol' => array(
-								'https',
-								'http',
-								'data',
-								'absolute',
-							),
-						),
-						'validate_keyframes' => false,
-					),
-					'max_bytes' => 50000,
-					'max_bytes_spec_url' => 'https://www.ampproject.org/docs/reference/spec#maximum-size',
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'head',
-					'spec_name' => 'style amp-custom',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#stylesheets',
-					'unique' => true,
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'amp-boilerplate' => array(
-						'dispatch_key' => 3,
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'nonce' => array(),
-				),
-				'cdata' => array(
-					'cdata_regex' => '\\s*body\\s*{\\s*-webkit-animation:\\s*-amp-start\\s+8s\\s+steps\\(1,\\s*end\\)\\s+0s\\s+1\\s+normal\\s+both;\\s*-moz-animation:\\s*-amp-start\\s+8s\\s+steps\\s*\\(1\\s*,\\s*end\\s*\\)\\s+0s\\s+1\\s+normal\\s+both;\\s*-ms-animation:\\s*-amp-start\\s+8s\\s+steps\\s*\\(1\\s*,\\s*end\\s*\\)\\s+0s\\s+1\\s+normal\\s+both;\\s*animation:\\s*-amp-start\\s+8s\\s+steps\\(1,\\s*end\\)\\s+0s\\s+1\\s+normal\\s+both;?\\s*}\\s*@-webkit-keyframes\\s+-amp-start\\s*{\\s*from\\s*{\\s*visibility:\\s*hidden;?\\s*}\\s*to\\s*{\\s*visibility:\\s*visible;?\\s*}\\s*}\\s*@-moz-keyframes\\s+-amp-start\\s*{\\s*from\\s*{\\s*visibility:\\s*hidden;?\\s*}\\s*to\\s*{\\s*visibility:\\s*visible;?\\s*}\\s*}\\s*@-ms-keyframes\\s+-amp-start\\s*{\\s*from\\s*{\\s*visibility:\\s*hidden;?\\s*}\\s*to\\s*{\\s*visibility:\\s*visible;?\\s*}\\s*}\\s*@-o-keyframes\\s+-amp-start\\s*{\\s*from\\s*{\\s*visibility:\\s*hidden;?\\s*}\\s*to\\s*{\\s*visibility:\\s*visible;?\\s*}\\s*}\\s*@keyframes\\s+-amp-start\\s*{\\s*from\\s*{\\s*visibility:\\s*hidden;?\\s*}\\s*to\\s*{\\s*visibility:\\s*visible;?\\s*}\\s*}\\s*',
-				),
-				'tag_spec' => array(
-					'mandatory_alternatives' => 'head > style[amp-boilerplate]',
-					'mandatory_parent' => 'head',
-					'spec_name' => 'head > style[amp-boilerplate]',
-					'spec_url' => 'https://github.com/ampproject/amphtml/blob/master/spec/amp-boilerplate.md',
-					'unique' => true,
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'amp-boilerplate' => array(
-						'dispatch_key' => 3,
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'nonce' => array(),
-				),
-				'cdata' => array(
-					'cdata_regex' => '\\s*body\\s*{\\s*-webkit-animation:\\s*none;\\s*-moz-animation:\\s*none;\\s*-ms-animation:\\s*none;\\s*animation:\\s*none;?\\s*}\\s*',
-				),
-				'tag_spec' => array(
-					'mandatory_alternatives' => 'noscript > style[amp-boilerplate]',
-					'mandatory_ancestor' => 'head',
-					'mandatory_parent' => 'noscript',
-					'spec_name' => 'noscript > style[amp-boilerplate]',
-					'spec_url' => 'https://github.com/ampproject/amphtml/blob/master/spec/amp-boilerplate.md',
-					'unique' => true,
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'amp-keyframes' => array(
-						'dispatch_key' => 1,
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-				),
-				'cdata' => array(
-					'css_spec' => array(
-						'allowed_at_rules' => array(
-							'keyframes',
-							'media',
-							'supports',
-						),
-						'declaration' => array(
-							'animation-timing-function',
-							'offset-distance',
-							'opacity',
-							'transform',
-							'visibility',
-						),
-						'font_url_spec' => array(),
-						'image_url_spec' => array(),
-						'validate_keyframes' => true,
-					),
-					'max_bytes' => 500000,
-					'max_bytes_spec_url' => 'https://www.ampproject.org/docs/reference/spec#keyframes-stylesheet',
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'body',
-					'spec_name' => 'style[amp-keyframes]',
-					'unique' => true,
-				),
-			),
-		),
-		'sub' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'sup' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'svg' => array(
-			array(
-				'attr_spec_list' => array(
-					'alignment-baseline' => array(),
-					'baseline-shift' => array(),
-					'clip' => array(),
-					'clip-path' => array(),
-					'clip-rule' => array(),
-					'color' => array(),
-					'color-interpolation' => array(),
-					'color-interpolation-filters' => array(),
-					'color-profile' => array(),
-					'color-rendering' => array(),
-					'contentscripttype' => array(),
-					'contentstyletype' => array(),
-					'cursor' => array(),
-					'direction' => array(),
-					'display' => array(),
-					'dominant-baseline' => array(),
-					'enable-background' => array(),
-					'externalresourcesrequired' => array(),
-					'fill' => array(),
-					'fill-opacity' => array(),
-					'fill-rule' => array(),
-					'filter' => array(),
-					'flood-color' => array(),
-					'flood-opacity' => array(),
-					'focusable' => array(),
-					'font-family' => array(),
-					'font-size' => array(),
-					'font-size-adjust' => array(),
-					'font-stretch' => array(),
-					'font-style' => array(),
-					'font-variant' => array(),
-					'font-weight' => array(),
-					'glyph-orientation-horizontal' => array(),
-					'glyph-orientation-vertical' => array(),
-					'height' => array(),
-					'image-rendering' => array(),
-					'kerning' => array(),
-					'letter-spacing' => array(),
-					'lighting-color' => array(),
-					'marker-end' => array(),
-					'marker-mid' => array(),
-					'marker-start' => array(),
-					'mask' => array(),
-					'opacity' => array(),
-					'overflow' => array(),
-					'pointer-events' => array(),
-					'preserveaspectratio' => array(),
-					'requiredextensions' => array(),
-					'requiredfeatures' => array(),
-					'shape-rendering' => array(),
-					'stop-color' => array(),
-					'stop-opacity' => array(),
-					'stroke' => array(),
-					'stroke-dasharray' => array(),
-					'stroke-dashoffset' => array(),
-					'stroke-linecap' => array(),
-					'stroke-linejoin' => array(),
-					'stroke-miterlimit' => array(),
-					'stroke-opacity' => array(),
-					'stroke-width' => array(),
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'systemlanguage' => array(),
-					'text-anchor' => array(),
-					'text-decoration' => array(),
-					'text-rendering' => array(),
-					'unicode-bidi' => array(),
-					'vector-effect' => array(),
-					'version' => array(
-						'value' => array(
-							'1.0',
-							'1.1',
-						),
-					),
-					'viewbox' => array(),
-					'visibility' => array(),
-					'width' => array(),
-					'word-spacing' => array(),
-					'writing-mode' => array(),
-					'x' => array(),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-					'y' => array(),
-					'zoomandpan' => array(),
-				),
-				'tag_spec' => array(
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'switch' => array(
-			array(
-				'attr_spec_list' => array(
-					'alignment-baseline' => array(),
-					'baseline-shift' => array(),
-					'clip' => array(),
-					'clip-path' => array(),
-					'clip-rule' => array(),
-					'color' => array(),
-					'color-interpolation' => array(),
-					'color-interpolation-filters' => array(),
-					'color-profile' => array(),
-					'color-rendering' => array(),
-					'cursor' => array(),
-					'direction' => array(),
-					'display' => array(),
-					'dominant-baseline' => array(),
-					'enable-background' => array(),
-					'fill' => array(),
-					'fill-opacity' => array(),
-					'fill-rule' => array(),
-					'filter' => array(),
-					'flood-color' => array(),
-					'flood-opacity' => array(),
-					'focusable' => array(),
-					'font-family' => array(),
-					'font-size' => array(),
-					'font-size-adjust' => array(),
-					'font-stretch' => array(),
-					'font-style' => array(),
-					'font-variant' => array(),
-					'font-weight' => array(),
-					'glyph-orientation-horizontal' => array(),
-					'glyph-orientation-vertical' => array(),
-					'image-rendering' => array(),
-					'kerning' => array(),
-					'letter-spacing' => array(),
-					'lighting-color' => array(),
-					'marker-end' => array(),
-					'marker-mid' => array(),
-					'marker-start' => array(),
-					'mask' => array(),
-					'opacity' => array(),
-					'overflow' => array(),
-					'pointer-events' => array(),
-					'requiredextensions' => array(),
-					'requiredfeatures' => array(),
-					'shape-rendering' => array(),
-					'stop-color' => array(),
-					'stop-opacity' => array(),
-					'stroke' => array(),
-					'stroke-dasharray' => array(),
-					'stroke-dashoffset' => array(),
-					'stroke-linecap' => array(),
-					'stroke-linejoin' => array(),
-					'stroke-miterlimit' => array(),
-					'stroke-opacity' => array(),
-					'stroke-width' => array(),
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'systemlanguage' => array(),
-					'text-anchor' => array(),
-					'text-decoration' => array(),
-					'text-rendering' => array(),
-					'unicode-bidi' => array(),
-					'vector-effect' => array(),
-					'visibility' => array(),
-					'word-spacing' => array(),
-					'writing-mode' => array(),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'svg',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'symbol' => array(
-			array(
-				'attr_spec_list' => array(
-					'alignment-baseline' => array(),
-					'baseline-shift' => array(),
-					'clip' => array(),
-					'clip-path' => array(),
-					'clip-rule' => array(),
-					'color' => array(),
-					'color-interpolation' => array(),
-					'color-interpolation-filters' => array(),
-					'color-profile' => array(),
-					'color-rendering' => array(),
-					'cursor' => array(),
-					'direction' => array(),
-					'display' => array(),
-					'dominant-baseline' => array(),
-					'enable-background' => array(),
-					'externalresourcesrequired' => array(),
-					'fill' => array(),
-					'fill-opacity' => array(),
-					'fill-rule' => array(),
-					'filter' => array(),
-					'flood-color' => array(),
-					'flood-opacity' => array(),
-					'focusable' => array(),
-					'font-family' => array(),
-					'font-size' => array(),
-					'font-size-adjust' => array(),
-					'font-stretch' => array(),
-					'font-style' => array(),
-					'font-variant' => array(),
-					'font-weight' => array(),
-					'glyph-orientation-horizontal' => array(),
-					'glyph-orientation-vertical' => array(),
-					'image-rendering' => array(),
-					'kerning' => array(),
-					'letter-spacing' => array(),
-					'lighting-color' => array(),
-					'marker-end' => array(),
-					'marker-mid' => array(),
-					'marker-start' => array(),
-					'mask' => array(),
-					'opacity' => array(),
-					'overflow' => array(),
-					'pointer-events' => array(),
-					'preserveaspectratio' => array(),
-					'shape-rendering' => array(),
-					'stop-color' => array(),
-					'stop-opacity' => array(),
-					'stroke' => array(),
-					'stroke-dasharray' => array(),
-					'stroke-dashoffset' => array(),
-					'stroke-linecap' => array(),
-					'stroke-linejoin' => array(),
-					'stroke-miterlimit' => array(),
-					'stroke-opacity' => array(),
-					'stroke-width' => array(),
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'text-anchor' => array(),
-					'text-decoration' => array(),
-					'text-rendering' => array(),
-					'unicode-bidi' => array(),
-					'vector-effect' => array(),
-					'viewbox' => array(),
-					'visibility' => array(),
-					'word-spacing' => array(),
-					'writing-mode' => array(),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'svg',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'table' => array(
-			array(
-				'attr_spec_list' => array(
-					'align' => array(),
-					'bgcolor' => array(),
-					'border' => array(
-						'value' => array(
-							'0',
-							'1',
-						),
-					),
-					'cellpadding' => array(),
-					'cellspacing' => array(),
-					'sortable' => array(),
-					'width' => array(),
-				),
-				'tag_spec' => array(),
-			),
-		),
-		'tbody' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'td' => array(
-			array(
-				'attr_spec_list' => array(
-					'align' => array(),
-					'bgcolor' => array(),
-					'colspan' => array(),
-					'headers' => array(),
-					'height' => array(),
-					'rowspan' => array(),
-					'valign' => array(),
-					'width' => array(),
-				),
-				'tag_spec' => array(),
-			),
-		),
-		'template' => array(
-			array(
-				'attr_spec_list' => array(
-					'date-template' => array(
-						'dispatch_key' => 1,
-						'mandatory' => true,
-						'value' => array(
-							'',
-						),
-					),
-					'dates' => array(),
-					'default' => array(),
-					'type' => array(
-						'mandatory' => true,
-						'value' => array(
-							'amp-mustache',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'amp-date-picker',
-					'requires_extension' => array(
-						'amp-mustache',
-					),
-					'spec_name' => 'amp-date-picker > template [date-template]',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'info-template' => array(
-						'dispatch_key' => 1,
-						'mandatory' => true,
-					),
-					'type' => array(
-						'mandatory' => true,
-						'value' => array(
-							'amp-mustache',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'amp-date-picker',
-					'requires_extension' => array(
-						'amp-mustache',
-					),
-					'spec_name' => 'amp-date-picker > template [info-template]',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'type' => array(
-						'mandatory' => true,
-						'value' => array(
-							'amp-mustache',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'disallowed_ancestor' => array(
-						'template',
-						'amp-date-picker',
-						'amp-story-auto-ads',
-						'form div [submit-success][template]',
-						'form div [submit-error][template]',
-						'form div [submitting][template]',
-						'form div [verify-error][template]',
-					),
-					'requires_extension' => array(
-						'amp-mustache',
-					),
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'type' => array(
-						'dispatch_key' => 3,
-						'mandatory' => true,
-						'value' => array(
-							'amp-mustache',
-						),
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'amp-story-auto-ads',
-					'reference_points' => array(
-						'AMP-STORY-GRID-LAYER animate-in' => array(
-							'mandatory' => false,
-							'unique' => false,
-						),
-						'AMP-STORY-GRID-LAYER default' => array(
-							'mandatory' => false,
-							'unique' => false,
-						),
-					),
-					'requires_extension' => array(
-						'amp-mustache',
-					),
-					'spec_name' => 'amp-story-auto-ads > template',
-				),
-			),
-		),
-		'text' => array(
-			array(
-				'attr_spec_list' => array(
-					'alignment-baseline' => array(),
-					'baseline-shift' => array(),
-					'clip' => array(),
-					'clip-path' => array(),
-					'clip-rule' => array(),
-					'color' => array(),
-					'color-interpolation' => array(),
-					'color-interpolation-filters' => array(),
-					'color-profile' => array(),
-					'color-rendering' => array(),
-					'cursor' => array(),
-					'direction' => array(),
-					'display' => array(),
-					'dominant-baseline' => array(),
-					'dx' => array(),
-					'dy' => array(),
-					'enable-background' => array(),
-					'externalresourcesrequired' => array(),
-					'fill' => array(),
-					'fill-opacity' => array(),
-					'fill-rule' => array(),
-					'filter' => array(),
-					'flood-color' => array(),
-					'flood-opacity' => array(),
-					'focusable' => array(),
-					'font-family' => array(),
-					'font-size' => array(),
-					'font-size-adjust' => array(),
-					'font-stretch' => array(),
-					'font-style' => array(),
-					'font-variant' => array(),
-					'font-weight' => array(),
-					'glyph-orientation-horizontal' => array(),
-					'glyph-orientation-vertical' => array(),
-					'image-rendering' => array(),
-					'kerning' => array(),
-					'lengthadjust' => array(),
-					'letter-spacing' => array(),
-					'lighting-color' => array(),
-					'marker-end' => array(),
-					'marker-mid' => array(),
-					'marker-start' => array(),
-					'mask' => array(),
-					'opacity' => array(),
-					'overflow' => array(),
-					'pointer-events' => array(),
-					'requiredextensions' => array(),
-					'requiredfeatures' => array(),
-					'rotate' => array(),
-					'shape-rendering' => array(),
-					'stop-color' => array(),
-					'stop-opacity' => array(),
-					'stroke' => array(),
-					'stroke-dasharray' => array(),
-					'stroke-dashoffset' => array(),
-					'stroke-linecap' => array(),
-					'stroke-linejoin' => array(),
-					'stroke-miterlimit' => array(),
-					'stroke-opacity' => array(),
-					'stroke-width' => array(),
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'systemlanguage' => array(),
-					'text-anchor' => array(),
-					'text-decoration' => array(),
-					'text-rendering' => array(),
-					'textlength' => array(),
-					'transform' => array(),
-					'unicode-bidi' => array(),
-					'vector-effect' => array(),
-					'visibility' => array(),
-					'word-spacing' => array(),
-					'writing-mode' => array(),
-					'x' => array(),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-					'y' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'svg',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'textarea' => array(
-			array(
-				'attr_spec_list' => array(
-					'[autocomplete]' => array(),
-					'[autofocus]' => array(),
-					'[cols]' => array(),
-					'[disabled]' => array(),
-					'[maxlength]' => array(),
-					'[minlength]' => array(),
-					'[placeholder]' => array(),
-					'[readonly]' => array(),
-					'[required]' => array(),
-					'[rows]' => array(),
-					'[selectiondirection]' => array(),
-					'[selectionend]' => array(),
-					'[selectionstart]' => array(),
-					'[spellcheck]' => array(),
-					'[wrap]' => array(),
-					'autocomplete' => array(),
-					'autofocus' => array(),
-					'cols' => array(),
-					'disabled' => array(),
-					'maxlength' => array(),
-					'minlength' => array(),
-					'name' => array(
-						'blacklisted_value_regex' => '(^|\\s)(__amp_\\S*|__count__|__defineGetter__|__defineSetter__|__lookupGetter__|__lookupSetter__|__noSuchMethod__|__parent__|__proto__|__AMP_\\S*|\\$p|\\$proxy|acceptCharset|addEventListener|appendChild|assignedSlot|attachShadow|baseURI|checkValidity|childElementCount|childNodes|classList|className|clientHeight|clientLeft|clientTop|clientWidth|compareDocumentPosition|computedName|computedRole|contentEditable|createShadowRoot|enqueAction|firstChild|firstElementChild|getAnimations|getAttribute|getAttributeNS|getAttributeNode|getAttributeNodeNS|getBoundingClientRect|getClientRects|getDestinationInsertionPoints|getElementsByClassName|getElementsByTagName|getElementsByTagNameNS|getRootNode|hasAttribute|hasAttributeNS|hasAttributes|hasChildNodes|hasPointerCapture|innerHTML|innerText|inputMode|insertAdjacentElement|insertAdjacentHTML|insertAdjacentText|isContentEditable|isDefaultNamespace|isEqualNode|isSameNode|lastChild|lastElementChild|lookupNamespaceURI|namespaceURI|nextElementSibling|nextSibling|nodeName|nodeType|nodeValue|offsetHeight|offsetLeft|offsetParent|offsetTop|offsetWidth|outerHTML|outerText|ownerDocument|parentElement|parentNode|previousElementSibling|previousSibling|querySelector|querySelectorAll|releasePointerCapture|removeAttribute|removeAttributeNS|removeAttributeNode|removeChild|removeEventListener|replaceChild|reportValidity|requestPointerLock|scrollHeight|scrollIntoView|scrollIntoViewIfNeeded|scrollLeft|scrollWidth|setAttribute|setAttributeNS|setAttributeNode|setAttributeNodeNS|setPointerCapture|shadowRoot|styleMap|tabIndex|tagName|textContent|toString|valueOf|(webkit|ms|moz|o)dropzone|(webkit|moz|ms|o)MatchesSelector|(webkit|moz|ms|o)RequestFullScreen|(webkit|moz|ms|o)RequestFullscreen)(\\s|$)',
-					),
-					'no-verify' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'placeholder' => array(),
-					'readonly' => array(),
-					'required' => array(),
-					'rows' => array(),
-					'selectiondirection' => array(),
-					'selectionend' => array(),
-					'selectionstart' => array(),
-					'spellcheck' => array(),
-					'wrap' => array(),
-				),
-				'tag_spec' => array(
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-form',
-				),
-			),
-		),
-		'textpath' => array(
-			array(
-				'attr_spec_list' => array(
-					'alignment-baseline' => array(),
-					'baseline-shift' => array(),
-					'clip' => array(),
-					'clip-path' => array(),
-					'clip-rule' => array(),
-					'color' => array(),
-					'color-interpolation' => array(),
-					'color-interpolation-filters' => array(),
-					'color-profile' => array(),
-					'color-rendering' => array(),
-					'cursor' => array(),
-					'direction' => array(),
-					'display' => array(),
-					'dominant-baseline' => array(),
-					'enable-background' => array(),
-					'externalresourcesrequired' => array(),
-					'fill' => array(),
-					'fill-opacity' => array(),
-					'fill-rule' => array(),
-					'filter' => array(),
-					'flood-color' => array(),
-					'flood-opacity' => array(),
-					'focusable' => array(),
-					'font-family' => array(),
-					'font-size' => array(),
-					'font-size-adjust' => array(),
-					'font-stretch' => array(),
-					'font-style' => array(),
-					'font-variant' => array(),
-					'font-weight' => array(),
-					'glyph-orientation-horizontal' => array(),
-					'glyph-orientation-vertical' => array(),
-					'image-rendering' => array(),
-					'kerning' => array(),
-					'letter-spacing' => array(),
-					'lighting-color' => array(),
-					'marker-end' => array(),
-					'marker-mid' => array(),
-					'marker-start' => array(),
-					'mask' => array(),
-					'method' => array(),
-					'opacity' => array(),
-					'overflow' => array(),
-					'pointer-events' => array(),
-					'requiredextensions' => array(),
-					'requiredfeatures' => array(),
-					'shape-rendering' => array(),
-					'spacing' => array(),
-					'startoffset' => array(),
-					'stop-color' => array(),
-					'stop-opacity' => array(),
-					'stroke' => array(),
-					'stroke-dasharray' => array(),
-					'stroke-dashoffset' => array(),
-					'stroke-linecap' => array(),
-					'stroke-linejoin' => array(),
-					'stroke-miterlimit' => array(),
-					'stroke-opacity' => array(),
-					'stroke-width' => array(),
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'systemlanguage' => array(),
-					'text-anchor' => array(),
-					'text-decoration' => array(),
-					'text-rendering' => array(),
-					'unicode-bidi' => array(),
-					'vector-effect' => array(),
-					'visibility' => array(),
-					'word-spacing' => array(),
-					'writing-mode' => array(),
-					'xlink:actuate' => array(),
-					'xlink:arcrole' => array(),
-					'xlink:href' => array(
-						'alternative_names' => array(
-							'href',
-						),
-						'value_url' => array(
-							'allow_empty' => false,
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
-					'xlink:role' => array(),
-					'xlink:show' => array(),
-					'xlink:title' => array(),
-					'xlink:type' => array(),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'svg',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'tfoot' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'th' => array(
-			array(
-				'attr_spec_list' => array(
-					'abbr' => array(),
-					'align' => array(),
-					'bgcolor' => array(),
-					'colspan' => array(),
-					'headers' => array(),
-					'height' => array(),
-					'rowspan' => array(),
-					'scope' => array(),
-					'sorted' => array(),
-					'valign' => array(),
-					'width' => array(),
-				),
-				'tag_spec' => array(),
-			),
-		),
-		'thead' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'time' => array(
-			array(
-				'attr_spec_list' => array(
-					'datetime' => array(),
-				),
-				'tag_spec' => array(),
-			),
-		),
-		'title' => array(
-			array(
-				'attr_spec_list' => array(
-					'[text]' => array(),
-				),
-				'tag_spec' => array(
-					'spec_name' => 'title',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'svg',
-					'spec_name' => 'svg title',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'tr' => array(
-			array(
-				'attr_spec_list' => array(
-					'align' => array(),
-					'bgcolor' => array(),
-					'height' => array(),
-					'valign' => array(),
-				),
-				'tag_spec' => array(),
-			),
-		),
-		'track' => array(
-			array(
-				'attr_spec_list' => array(
-					'default' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'kind' => array(
-						'value' => array(
-							'captions',
-							'chapters',
-							'descriptions',
-							'metadata',
-						),
-					),
-					'label' => array(),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'srclang' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'audio',
-					'spec_name' => 'audio > track',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'default' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'kind' => array(
-						'mandatory' => true,
-						'value_casei' => array(
-							'subtitles',
-						),
-					),
-					'label' => array(),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'srclang' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'audio',
-					'spec_name' => 'audio > track[kind=subtitles]',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'default' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'kind' => array(
-						'value' => array(
-							'captions',
-							'chapters',
-							'descriptions',
-							'metadata',
-						),
-					),
-					'label' => array(),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'srclang' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'video',
-					'spec_name' => 'video > track',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'default' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'kind' => array(
-						'mandatory' => true,
-						'value_casei' => array(
-							'subtitles',
-						),
-					),
-					'label' => array(),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'srclang' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'video',
-					'spec_name' => 'video > track[kind=subtitles]',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'[label]' => array(),
-					'[src]' => array(),
-					'[srclang]' => array(),
-					'default' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'kind' => array(
-						'value' => array(
-							'captions',
-							'chapters',
-							'descriptions',
-							'metadata',
-						),
-					),
-					'label' => array(),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'srclang' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'amp-audio',
-					'spec_name' => 'amp-audio > track',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'[label]' => array(),
-					'[src]' => array(),
-					'[srclang]' => array(),
-					'default' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'kind' => array(
-						'mandatory' => true,
-						'value_casei' => array(
-							'subtitles',
-						),
-					),
-					'label' => array(),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'srclang' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'amp-audio',
-					'spec_name' => 'amp-audio > track[kind=subtitles]',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'[label]' => array(),
-					'[src]' => array(),
-					'[srclang]' => array(),
-					'default' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'kind' => array(
-						'value' => array(
-							'captions',
-							'chapters',
-							'descriptions',
-							'metadata',
-						),
-					),
-					'label' => array(),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'srclang' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'amp-video',
-					'spec_name' => 'amp-video > track',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'[label]' => array(),
-					'[src]' => array(),
-					'[srclang]' => array(),
-					'default' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'kind' => array(
-						'mandatory' => true,
-						'value_casei' => array(
-							'subtitles',
-						),
-					),
-					'label' => array(),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'srclang' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'amp-video',
-					'spec_name' => 'amp-video > track[kind=subtitles]',
-				),
-			),
-			array(
-				'attr_spec_list' => array(
-					'[label]' => array(),
-					'[src]' => array(),
-					'[srclang]' => array(),
-					'default' => array(
-						'value' => array(
-							'',
-						),
-					),
-					'kind' => array(
-						'mandatory' => true,
-						'value_casei' => array(
-							'subtitles',
-						),
-					),
-					'label' => array(),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'mandatory' => true,
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'https',
-							),
-						),
-					),
-					'srclang' => array(
-						'mandatory' => true,
-					),
-				),
-				'tag_spec' => array(
-					'mandatory_parent' => 'amp-ima-video',
-					'spec_name' => 'amp-ima-video > track[kind=subtitles]',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-ima-video',
-				),
-			),
-		),
-		'tref' => array(
-			array(
-				'attr_spec_list' => array(
-					'alignment-baseline' => array(),
-					'baseline-shift' => array(),
-					'clip' => array(),
-					'clip-path' => array(),
-					'clip-rule' => array(),
-					'color' => array(),
-					'color-interpolation' => array(),
-					'color-interpolation-filters' => array(),
-					'color-profile' => array(),
-					'color-rendering' => array(),
-					'cursor' => array(),
-					'direction' => array(),
-					'display' => array(),
-					'dominant-baseline' => array(),
-					'enable-background' => array(),
-					'externalresourcesrequired' => array(),
-					'fill' => array(),
-					'fill-opacity' => array(),
-					'fill-rule' => array(),
-					'filter' => array(),
-					'flood-color' => array(),
-					'flood-opacity' => array(),
-					'focusable' => array(),
-					'font-family' => array(),
-					'font-size' => array(),
-					'font-size-adjust' => array(),
-					'font-stretch' => array(),
-					'font-style' => array(),
-					'font-variant' => array(),
-					'font-weight' => array(),
-					'glyph-orientation-horizontal' => array(),
-					'glyph-orientation-vertical' => array(),
-					'image-rendering' => array(),
-					'kerning' => array(),
-					'letter-spacing' => array(),
-					'lighting-color' => array(),
-					'marker-end' => array(),
-					'marker-mid' => array(),
-					'marker-start' => array(),
-					'mask' => array(),
-					'opacity' => array(),
-					'overflow' => array(),
-					'pointer-events' => array(),
-					'requiredextensions' => array(),
-					'requiredfeatures' => array(),
-					'shape-rendering' => array(),
-					'stop-color' => array(),
-					'stop-opacity' => array(),
-					'stroke' => array(),
-					'stroke-dasharray' => array(),
-					'stroke-dashoffset' => array(),
-					'stroke-linecap' => array(),
-					'stroke-linejoin' => array(),
-					'stroke-miterlimit' => array(),
-					'stroke-opacity' => array(),
-					'stroke-width' => array(),
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'systemlanguage' => array(),
-					'text-anchor' => array(),
-					'text-decoration' => array(),
-					'text-rendering' => array(),
-					'unicode-bidi' => array(),
-					'vector-effect' => array(),
-					'visibility' => array(),
-					'word-spacing' => array(),
-					'writing-mode' => array(),
-					'xlink:actuate' => array(),
-					'xlink:arcrole' => array(),
-					'xlink:href' => array(
-						'alternative_names' => array(
-							'href',
-						),
-						'value_url' => array(
-							'allow_empty' => false,
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
-					'xlink:role' => array(),
-					'xlink:show' => array(),
-					'xlink:title' => array(),
-					'xlink:type' => array(),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'svg',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'tspan' => array(
-			array(
-				'attr_spec_list' => array(
-					'alignment-baseline' => array(),
-					'baseline-shift' => array(),
-					'clip' => array(),
-					'clip-path' => array(),
-					'clip-rule' => array(),
-					'color' => array(),
-					'color-interpolation' => array(),
-					'color-interpolation-filters' => array(),
-					'color-profile' => array(),
-					'color-rendering' => array(),
-					'cursor' => array(),
-					'direction' => array(),
-					'display' => array(),
-					'dominant-baseline' => array(),
-					'dx' => array(),
-					'dy' => array(),
-					'enable-background' => array(),
-					'externalresourcesrequired' => array(),
-					'fill' => array(),
-					'fill-opacity' => array(),
-					'fill-rule' => array(),
-					'filter' => array(),
-					'flood-color' => array(),
-					'flood-opacity' => array(),
-					'focusable' => array(),
-					'font-family' => array(),
-					'font-size' => array(),
-					'font-size-adjust' => array(),
-					'font-stretch' => array(),
-					'font-style' => array(),
-					'font-variant' => array(),
-					'font-weight' => array(),
-					'glyph-orientation-horizontal' => array(),
-					'glyph-orientation-vertical' => array(),
-					'image-rendering' => array(),
-					'kerning' => array(),
-					'lengthadjust' => array(),
-					'letter-spacing' => array(),
-					'lighting-color' => array(),
-					'marker-end' => array(),
-					'marker-mid' => array(),
-					'marker-start' => array(),
-					'mask' => array(),
-					'opacity' => array(),
-					'overflow' => array(),
-					'pointer-events' => array(),
-					'requiredextensions' => array(),
-					'requiredfeatures' => array(),
-					'rotate' => array(),
-					'shape-rendering' => array(),
-					'stop-color' => array(),
-					'stop-opacity' => array(),
-					'stroke' => array(),
-					'stroke-dasharray' => array(),
-					'stroke-dashoffset' => array(),
-					'stroke-linecap' => array(),
-					'stroke-linejoin' => array(),
-					'stroke-miterlimit' => array(),
-					'stroke-opacity' => array(),
-					'stroke-width' => array(),
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'systemlanguage' => array(),
-					'text-anchor' => array(),
-					'text-decoration' => array(),
-					'text-rendering' => array(),
-					'textlength' => array(),
-					'unicode-bidi' => array(),
-					'vector-effect' => array(),
-					'visibility' => array(),
-					'word-spacing' => array(),
-					'writing-mode' => array(),
-					'x' => array(),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-					'y' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'svg',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'tt' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'u' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'ul' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'use' => array(
-			array(
-				'attr_spec_list' => array(
-					'alignment-baseline' => array(),
-					'baseline-shift' => array(),
-					'clip' => array(),
-					'clip-path' => array(),
-					'clip-rule' => array(),
-					'color' => array(),
-					'color-interpolation' => array(),
-					'color-interpolation-filters' => array(),
-					'color-profile' => array(),
-					'color-rendering' => array(),
-					'cursor' => array(),
-					'direction' => array(),
-					'display' => array(),
-					'dominant-baseline' => array(),
-					'enable-background' => array(),
-					'externalresourcesrequired' => array(),
-					'fill' => array(),
-					'fill-opacity' => array(),
-					'fill-rule' => array(),
-					'filter' => array(),
-					'flood-color' => array(),
-					'flood-opacity' => array(),
-					'focusable' => array(),
-					'font-family' => array(),
-					'font-size' => array(),
-					'font-size-adjust' => array(),
-					'font-stretch' => array(),
-					'font-style' => array(),
-					'font-variant' => array(),
-					'font-weight' => array(),
-					'glyph-orientation-horizontal' => array(),
-					'glyph-orientation-vertical' => array(),
-					'height' => array(),
-					'image-rendering' => array(),
-					'kerning' => array(),
-					'letter-spacing' => array(),
-					'lighting-color' => array(),
-					'marker-end' => array(),
-					'marker-mid' => array(),
-					'marker-start' => array(),
-					'mask' => array(),
-					'opacity' => array(),
-					'overflow' => array(),
-					'pointer-events' => array(),
-					'requiredextensions' => array(),
-					'requiredfeatures' => array(),
-					'shape-rendering' => array(),
-					'stop-color' => array(),
-					'stop-opacity' => array(),
-					'stroke' => array(),
-					'stroke-dasharray' => array(),
-					'stroke-dashoffset' => array(),
-					'stroke-linecap' => array(),
-					'stroke-linejoin' => array(),
-					'stroke-miterlimit' => array(),
-					'stroke-opacity' => array(),
-					'stroke-width' => array(),
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'systemlanguage' => array(),
-					'text-anchor' => array(),
-					'text-decoration' => array(),
-					'text-rendering' => array(),
-					'transform' => array(),
-					'unicode-bidi' => array(),
-					'vector-effect' => array(),
-					'visibility' => array(),
-					'width' => array(),
-					'word-spacing' => array(),
-					'writing-mode' => array(),
-					'x' => array(),
-					'xlink:actuate' => array(),
-					'xlink:arcrole' => array(),
-					'xlink:href' => array(
-						'alternative_names' => array(
-							'href',
-						),
-						'value_url' => array(
-							'allow_empty' => false,
-							'protocol' => array(
-								'http',
-								'https',
-							),
-						),
-					),
-					'xlink:role' => array(),
-					'xlink:show' => array(),
-					'xlink:title' => array(),
-					'xlink:type' => array(),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-					'y' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'svg',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'var' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-		'video' => array(
-			array(
-				'attr_spec_list' => array(
-					'autoplay' => array(),
-					'controls' => array(),
-					'height' => array(),
-					'loop' => array(),
-					'muted' => array(),
-					'playsinline' => array(),
-					'poster' => array(),
-					'preload' => array(),
-					'src' => array(
-						'blacklisted_value_regex' => '__amp_source_origin',
-						'value_url' => array(
-							'allow_relative' => false,
-							'protocol' => array(
-								'data',
-								'https',
-							),
-						),
-					),
-					'width' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'noscript',
-					'mandatory_ancestor_suggested_alternative' => 'amp-video',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-video',
-				),
-			),
-		),
-		'view' => array(
-			array(
-				'attr_spec_list' => array(
-					'externalresourcesrequired' => array(),
-					'preserveaspectratio' => array(),
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'viewbox' => array(),
-					'viewtarget' => array(),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-					'zoomandpan' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'svg',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'vkern' => array(
-			array(
-				'attr_spec_list' => array(
-					'g1' => array(),
-					'g2' => array(),
-					'k' => array(),
-					'style' => array(
-						'blacklisted_value_regex' => '!important',
-					),
-					'u1' => array(),
-					'u2' => array(),
-					'xml:lang' => array(),
-					'xml:space' => array(),
-					'xmlns' => array(),
-					'xmlns:xlink' => array(),
-				),
-				'tag_spec' => array(
-					'mandatory_ancestor' => 'svg',
-					'spec_url' => 'https://www.ampproject.org/docs/reference/spec#svg',
-				),
-			),
-		),
-		'wbr' => array(
-			array(
-				'attr_spec_list' => array(),
-				'tag_spec' => array(),
-			),
-		),
-	);
-
-	private static $layout_allowed_attrs = array(
-		'[height]' => array(),
-		'[width]' => array(),
-		'height' => array(),
-		'heights' => array(),
-		'layout' => array(),
-		'sizes' => array(),
-		'width' => array(),
-	);
-
-
-	private static $globally_allowed_attrs = array(
-		'[aria-activedescendant]' => array(),
-		'[aria-atomic]' => array(),
-		'[aria-autocomplete]' => array(),
-		'[aria-busy]' => array(),
-		'[aria-checked]' => array(),
-		'[aria-controls]' => array(),
-		'[aria-describedby]' => array(),
-		'[aria-disabled]' => array(),
-		'[aria-dropeffect]' => array(),
-		'[aria-expanded]' => array(),
-		'[aria-flowto]' => array(),
-		'[aria-grabbed]' => array(),
-		'[aria-haspopup]' => array(),
-		'[aria-hidden]' => array(),
-		'[aria-invalid]' => array(),
-		'[aria-label]' => array(),
-		'[aria-labelledby]' => array(),
-		'[aria-level]' => array(),
-		'[aria-live]' => array(),
-		'[aria-multiline]' => array(),
-		'[aria-multiselectable]' => array(),
-		'[aria-orientation]' => array(),
-		'[aria-owns]' => array(),
-		'[aria-posinset]' => array(),
-		'[aria-pressed]' => array(),
-		'[aria-readonly]' => array(),
-		'[aria-relevant]' => array(),
-		'[aria-required]' => array(),
-		'[aria-selected]' => array(),
-		'[aria-setsize]' => array(),
-		'[aria-sort]' => array(),
-		'[aria-valuemax]' => array(),
-		'[aria-valuemin]' => array(),
-		'[aria-valuenow]' => array(),
-		'[aria-valuetext]' => array(),
-		'[class]' => array(),
-		'[hidden]' => array(),
-		'[text]' => array(),
-		'about' => array(),
-		'accesskey' => array(),
-		'amp-access' => array(),
-		'amp-access-behavior' => array(),
-		'amp-access-hide' => array(),
-		'amp-access-id' => array(),
-		'amp-access-loader' => array(),
-		'amp-access-loading' => array(),
-		'amp-access-off' => array(),
-		'amp-access-on' => array(),
-		'amp-access-show' => array(),
-		'amp-access-style' => array(),
-		'amp-access-template' => array(),
-		'amp-fx' => array(
-			'value_regex_casei' => '(fade-in|fade-in-scroll|fly-in-bottom|fly-in-left|fly-in-right|fly-in-top|parallax)(\\s|fade-in|fade-in-scroll|fly-in-bottom|fly-in-left|fly-in-right|fly-in-top|parallax)*',
-		),
-		'aria-activedescendant' => array(),
-		'aria-atomic' => array(),
-		'aria-autocomplete' => array(),
-		'aria-busy' => array(),
-		'aria-checked' => array(),
-		'aria-controls' => array(),
-		'aria-current' => array(),
-		'aria-describedby' => array(),
-		'aria-disabled' => array(),
-		'aria-dropeffect' => array(),
-		'aria-expanded' => array(),
-		'aria-flowto' => array(),
-		'aria-grabbed' => array(),
-		'aria-haspopup' => array(),
-		'aria-hidden' => array(),
-		'aria-invalid' => array(),
-		'aria-label' => array(),
-		'aria-labelledby' => array(),
-		'aria-level' => array(),
-		'aria-live' => array(),
-		'aria-multiline' => array(),
-		'aria-multiselectable' => array(),
-		'aria-orientation' => array(),
-		'aria-owns' => array(),
-		'aria-posinset' => array(),
-		'aria-pressed' => array(),
-		'aria-readonly' => array(),
-		'aria-relevant' => array(),
-		'aria-required' => array(),
-		'aria-selected' => array(),
-		'aria-setsize' => array(),
-		'aria-sort' => array(),
-		'aria-valuemax' => array(),
-		'aria-valuemin' => array(),
-		'aria-valuenow' => array(),
-		'aria-valuetext' => array(),
-		'class' => array(
-			'blacklisted_value_regex' => '(^|\\W)i-amphtml-',
-		),
-		'content' => array(),
-		'datatype' => array(),
-		'dir' => array(),
-		'draggable' => array(),
-		'fallback' => array(
-			'value' => array(
-				'',
-			),
-		),
-		'hidden' => array(
-			'value' => array(
-				'',
-			),
-		),
-		'i-amp-access-id' => array(),
-		'id' => array(
-			'blacklisted_value_regex' => '(^|\\s)(__amp_\\S*|__count__|__defineGetter__|__defineSetter__|__lookupGetter__|__lookupSetter__|__noSuchMethod__|__parent__|__proto__|__AMP_\\S*|\\$p|\\$proxy|acceptCharset|addEventListener|appendChild|assignedSlot|attachShadow|AMP|baseURI|checkValidity|childElementCount|childNodes|classList|className|clientHeight|clientLeft|clientTop|clientWidth|compareDocumentPosition|computedName|computedRole|contentEditable|createShadowRoot|enqueAction|firstChild|firstElementChild|getAnimations|getAttribute|getAttributeNS|getAttributeNode|getAttributeNodeNS|getBoundingClientRect|getClientRects|getDestinationInsertionPoints|getElementsByClassName|getElementsByTagName|getElementsByTagNameNS|getRootNode|hasAttribute|hasAttributeNS|hasAttributes|hasChildNodes|hasPointerCapture|i-amphtml-\\S*|innerHTML|innerText|inputMode|insertAdjacentElement|insertAdjacentHTML|insertAdjacentText|isContentEditable|isDefaultNamespace|isEqualNode|isSameNode|lastChild|lastElementChild|lookupNamespaceURI|namespaceURI|nextElementSibling|nextSibling|nodeName|nodeType|nodeValue|offsetHeight|offsetLeft|offsetParent|offsetTop|offsetWidth|outerHTML|outerText|ownerDocument|parentElement|parentNode|previousElementSibling|previousSibling|querySelector|querySelectorAll|releasePointerCapture|removeAttribute|removeAttributeNS|removeAttributeNode|removeChild|removeEventListener|replaceChild|reportValidity|requestPointerLock|scrollHeight|scrollIntoView|scrollIntoViewIfNeeded|scrollLeft|scrollWidth|setAttribute|setAttributeNS|setAttributeNode|setAttributeNodeNS|setPointerCapture|shadowRoot|styleMap|tabIndex|tagName|textContent|toString|valueOf|(webkit|ms|moz|o)dropzone|(webkit|moz|ms|o)MatchesSelector|(webkit|moz|ms|o)RequestFullScreen|(webkit|moz|ms|o)RequestFullscreen)(\\s|$)',
-		),
-		'inlist' => array(),
-		'itemid' => array(),
-		'itemprop' => array(),
-		'itemref' => array(),
-		'itemscope' => array(),
-		'itemtype' => array(),
-		'lang' => array(),
-		'on' => array(),
-		'overflow' => array(),
-		'placeholder' => array(
-			'value' => array(
-				'',
-			),
-		),
-		'prefix' => array(),
-		'property' => array(),
-		'rel' => array(
-			'blacklisted_value_regex' => '(^|\\s)(canonical|components|dns-prefetch|import|manifest|preconnect|preload|prerender|serviceworker|stylesheet|subresource)(\\s|$)',
-		),
-		'resource' => array(),
-		'rev' => array(),
-		'role' => array(),
-		'style' => array(
-			'blacklisted_value_regex' => '(!important|<!--)',
-		),
-		'subscriptions-action' => array(),
-		'subscriptions-actions' => array(
-			'value' => array(
-				'',
-			),
-		),
-		'subscriptions-decorate' => array(),
-		'subscriptions-dialog' => array(
-			'value' => array(
-				'',
-			),
-		),
-		'subscriptions-display' => array(),
-		'subscriptions-section' => array(
-			'value_casei' => array(
-				'actions',
-				'content',
-				'content-not-granted',
-				'loading',
-			),
-		),
-		'subscriptions-service' => array(),
-		'tabindex' => array(),
-		'title' => array(),
-		'translate' => array(),
-		'typeof' => array(),
-		'validation-for' => array(),
-		'visible-when-invalid' => array(
-			'value' => array(
-				'badInput',
-				'customError',
-				'patternMismatch',
-				'rangeOverflow',
-				'rangeUnderflow',
-				'stepMismatch',
-				'tooLong',
-				'typeMismatch',
-				'valueMissing',
-			),
-		),
-		'vocab' => array(),
-	);
-
-
-	private static $reference_points = array(
-		'AMP-CAROUSEL lightbox [child]' => array(
-			'attr_spec_list' => array(
-				'lightbox-thumbnail-id' => array(
-					'value_regex_casei' => '^[a-z][a-z\\d_-]*',
-				),
-			),
-			'tag_spec' => array(
-				'spec_name' => 'AMP-CAROUSEL lightbox [child]',
-			),
-		),
-		'AMP-CAROUSEL lightbox [lightbox-exclude]' => array(
-			'attr_spec_list' => array(
-				'lightbox-exclude' => array(
-					'mandatory' => true,
-				),
-			),
-			'tag_spec' => array(
-				'spec_name' => 'AMP-CAROUSEL lightbox [lightbox-exclude]',
-			),
-		),
-		'AMP-LIVE-LIST [items]' => array(
-			'attr_spec_list' => array(
-				'items' => array(
-					'mandatory' => true,
-				),
-			),
-			'tag_spec' => array(
-				'reference_points' => array(
-					'AMP-LIVE-LIST [items] item' => array(
-						'mandatory' => false,
-						'unique' => false,
-					),
-				),
-				'spec_name' => 'AMP-LIVE-LIST [items]',
-				'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-live-list#items',
-			),
-		),
-		'AMP-LIVE-LIST [items] item' => array(
-			'attr_spec_list' => array(
-				'data-sort-time' => array(
-					'mandatory' => true,
-				),
-				'data-tombstone' => array(),
-				'data-update-time' => array(),
-				'id' => array(
-					'mandatory' => true,
-				),
-			),
-			'tag_spec' => array(
-				'spec_name' => 'AMP-LIVE-LIST [items] item',
-				'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-live-list#items',
-			),
-		),
-		'AMP-LIVE-LIST [pagination]' => array(
-			'attr_spec_list' => array(
-				'pagination' => array(
-					'mandatory' => true,
-				),
-			),
-			'tag_spec' => array(
-				'spec_name' => 'AMP-LIVE-LIST [pagination]',
-				'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-live-list#pagination',
-			),
-		),
-		'AMP-LIVE-LIST [update]' => array(
-			'attr_spec_list' => array(
-				'update' => array(
-					'mandatory' => true,
-				),
-			),
-			'tag_spec' => array(
-				'spec_name' => 'AMP-LIVE-LIST [update]',
-				'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-live-list#update',
-			),
-		),
-		'AMP-NEXT-PAGE > [separator]' => array(
-			'attr_spec_list' => array(
-				'separator' => array(
-					'mandatory' => true,
-				),
-			),
-			'tag_spec' => array(
-				'mandatory_parent' => 'amp-next-page',
-				'spec_name' => 'AMP-NEXT-PAGE > [separator]',
-			),
-		),
-		'AMP-SELECTOR child' => array(
-			'attr_spec_list' => array(),
-			'tag_spec' => array(
-				'reference_points' => array(
-					'AMP-SELECTOR child' => array(
-						'mandatory' => false,
-						'unique' => false,
-					),
-					'AMP-SELECTOR option' => array(
-						'mandatory' => false,
-						'unique' => false,
-					),
-				),
-				'spec_name' => 'AMP-SELECTOR child',
-			),
-		),
-		'AMP-SELECTOR option' => array(
-			'attr_spec_list' => array(
-				'disabled' => array(
-					'value' => array(
-						'',
-					),
-				),
-				'option' => array(
-					'mandatory' => true,
-				),
-				'selected' => array(
-					'value' => array(
-						'',
-					),
-				),
-			),
-			'tag_spec' => array(
-				'spec_name' => 'AMP-SELECTOR option',
-				'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-selector',
-			),
-		),
-		'AMP-STORY-CTA-LAYER animate-in' => array(
-			'attr_spec_list' => array(
-				'animate-in' => array(
-					'value' => array(
-						'drop',
-						'fade-in',
-						'fly-in-bottom',
-						'fly-in-left',
-						'fly-in-right',
-						'fly-in-top',
-						'pan-down',
-						'pan-left',
-						'pan-right',
-						'pan-up',
-						'pulse',
-						'rotate-in-left',
-						'rotate-in-right',
-						'twirl-in',
-						'whoosh-in-left',
-						'whoosh-in-right',
-						'zoom-in',
-						'zoom-out',
-					),
-				),
-				'animate-in-after' => array(),
-				'animate-in-delay' => array(),
-				'animate-in-duration' => array(),
-			),
-			'tag_spec' => array(
-				'reference_points' => array(
-					'AMP-STORY-CTA-LAYER animate-in' => array(
-						'mandatory' => false,
-						'unique' => false,
-					),
-				),
-				'spec_name' => 'AMP-STORY-CTA-LAYER animate-in',
-				'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-story',
-			),
-		),
-		'AMP-STORY-GRID-LAYER animate-in' => array(
-			'attr_spec_list' => array(
-				'animate-in' => array(
-					'value' => array(
-						'drop',
-						'fade-in',
-						'fly-in-bottom',
-						'fly-in-left',
-						'fly-in-right',
-						'fly-in-top',
-						'pan-down',
-						'pan-left',
-						'pan-right',
-						'pan-up',
-						'pulse',
-						'rotate-in-left',
-						'rotate-in-right',
-						'twirl-in',
-						'whoosh-in-left',
-						'whoosh-in-right',
-						'zoom-in',
-						'zoom-out',
-					),
-				),
-				'animate-in-after' => array(),
-				'animate-in-delay' => array(),
-				'animate-in-duration' => array(),
-				'data-tooltip-icon' => array(
-					'value_url' => array(
-						'protocol' => array(
-							'http',
-							'https',
-							'data',
-						),
-					),
-				),
-				'target' => array(
-					'value' => array(
-						'_blank',
-					),
-				),
-			),
-			'tag_spec' => array(
-				'reference_points' => array(
-					'AMP-STORY-GRID-LAYER animate-in' => array(
-						'mandatory' => false,
-						'unique' => false,
-					),
-				),
-				'spec_name' => 'AMP-STORY-GRID-LAYER animate-in',
-				'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-story',
-			),
-		),
-		'AMP-STORY-GRID-LAYER default' => array(
-			'attr_spec_list' => array(
-				'align-content' => array(
-					'value' => array(
-						'center',
-						'end',
-						'space-around',
-						'space-between',
-						'space-evenly',
-						'start',
-						'stretch',
-					),
-				),
-				'align-items' => array(
-					'value' => array(
-						'center',
-						'end',
-						'start',
-						'stretch',
-					),
-				),
-				'align-self' => array(
-					'value' => array(
-						'center',
-						'end',
-						'start',
-						'stretch',
-					),
-				),
-				'animate-in' => array(
-					'value' => array(
-						'drop',
-						'fade-in',
-						'fly-in-bottom',
-						'fly-in-left',
-						'fly-in-right',
-						'fly-in-top',
-						'pan-down',
-						'pan-left',
-						'pan-right',
-						'pan-up',
-						'pulse',
-						'rotate-in-left',
-						'rotate-in-right',
-						'twirl-in',
-						'whoosh-in-left',
-						'whoosh-in-right',
-						'zoom-in',
-						'zoom-out',
-					),
-				),
-				'animate-in-after' => array(),
-				'animate-in-delay' => array(),
-				'animate-in-duration' => array(),
-				'data-tooltip-icon' => array(
-					'value_url' => array(
-						'protocol' => array(
-							'http',
-							'https',
-							'data',
-						),
-					),
-				),
-				'grid-area' => array(),
-				'justify-content' => array(
-					'value' => array(
-						'center',
-						'end',
-						'space-around',
-						'space-between',
-						'space-evenly',
-						'start',
-						'stretch',
-					),
-				),
-				'justify-items' => array(
-					'value' => array(
-						'center',
-						'end',
-						'start',
-						'stretch',
-					),
-				),
-				'justify-self' => array(
-					'value' => array(
-						'center',
-						'end',
-						'start',
-						'stretch',
-					),
-				),
-				'target' => array(
-					'value' => array(
-						'_blank',
-					),
-				),
-			),
-			'tag_spec' => array(
-				'reference_points' => array(
-					'AMP-STORY-GRID-LAYER animate-in' => array(
-						'mandatory' => false,
-						'unique' => false,
-					),
-				),
-				'spec_name' => 'AMP-STORY-GRID-LAYER default',
-				'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-story',
-			),
-		),
-		'AMP-VIDEO-IFRAME > [placeholder]' => array(
-			'attr_spec_list' => array(
-				'placeholder' => array(
-					'mandatory' => true,
-				),
-			),
-			'tag_spec' => array(
-				'spec_name' => 'AMP-VIDEO-IFRAME > [placeholder]',
-				'spec_url' => 'https://www.ampproject.org/docs/reference/components/amp-video-iframe',
-			),
-		),
-	);
-
-
-	/**
-	 * Get allowed tags.
-	 *
-	 * @since 0.5
-	 * @return array Allowed tags.
-	 */
-	public static function get_allowed_tags() {
-		return self::$allowed_tags;
-	}
-
-	/**
-	 * Get allowed tag.
-	 *
-	 * Get the rules for a single tag so that the entire data structure needn't be passed around.
-	 *
-	 * @since 0.7
-	 * @param string $node_name Tag name.
-	 * @return array|null Allowed tag, or null if the tag does not exist.
-	 */
-	public static function get_allowed_tag( $node_name ) {
-		if ( isset( self::$allowed_tags[ $node_name ] ) ) {
-			return self::$allowed_tags[ $node_name ];
-		}
-		return null;
-	}
-
-	/**
-	 * Get reference point spec.
-	 *
-	 * @since 1.0
-	 * @param string $tag_spec_name Tag spec name.
-	 * @return array|null Reference point spec, or null if does not exist.
-	 */
-	public static function get_reference_point_spec( $tag_spec_name ) {
-		if ( isset( self::$reference_points[ $tag_spec_name ] ) ) {
-			return self::$reference_points[ $tag_spec_name ];
-		}
-		return null;
-	}
-
-	/**
-	 * Get list of globally-allowed attributes.
-	 *
-	 * @since 0.5
-	 * @return array Allowed tag.
-	 */
-	public static function get_allowed_attributes() {
-		return self::$globally_allowed_attrs;
-	}
-
-	/**
-	 * Get layout attributes.
-	 *
-	 * @since 0.5
-	 * @return array Allowed tag.
-	 */
-	public static function get_layout_attributes() {
-		return self::$layout_allowed_attrs;
-	}
-
-}
diff --git a/includes/sanitizers/class-amp-audio-sanitizer.php b/includes/sanitizers/class-amp-audio-sanitizer.php
deleted file mode 100644
index 3622ccb2208..00000000000
--- a/includes/sanitizers/class-amp-audio-sanitizer.php
+++ /dev/null
@@ -1,172 +0,0 @@
-<?php
-/**
- * Class AMP_Audio_Sanitizer
- *
- * @package AMP
- */
-
-/**
- * Class AMP_Audio_Sanitizer
- *
- * Converts <audio> tags to <amp-audio>
- */
-class AMP_Audio_Sanitizer extends AMP_Base_Sanitizer {
-
-	/**
-	 * Tag.
-	 *
-	 * @var string HTML audio tag to identify and replace with AMP version.
-	 * @since 0.2
-	 */
-	public static $tag = 'audio';
-
-	/**
-	 * Get mapping of HTML selectors to the AMP component selectors which they may be converted into.
-	 *
-	 * @return array Mapping.
-	 */
-	public function get_selector_conversion_mapping() {
-		return array(
-			'audio' => array( 'amp-audio' ),
-		);
-	}
-
-	/**
-	 * Sanitize the <audio> elements from the HTML contained in this instance's DOMDocument.
-	 *
-	 * @since 0.2
-	 */
-	public function sanitize() {
-		$nodes     = $this->dom->getElementsByTagName( self::$tag );
-		$num_nodes = $nodes->length;
-		if ( 0 === $num_nodes ) {
-			return;
-		}
-
-		for ( $i = $num_nodes - 1; $i >= 0; $i-- ) {
-			$node           = $nodes->item( $i );
-			$amp_data       = $this->get_data_amp_attributes( $node );
-			$old_attributes = AMP_DOM_Utils::get_node_attributes_as_assoc_array( $node );
-			$old_attributes = $this->filter_data_amp_attributes( $old_attributes, $amp_data );
-
-			$new_attributes = $this->filter_attributes( $old_attributes );
-
-			$new_node = AMP_DOM_Utils::create_node( $this->dom, 'amp-audio', $new_attributes );
-
-			foreach ( $node->childNodes as $child_node ) {
-
-				/**
-				 * Child node.
-				 *
-				 * @todo: Fix when `source` has no closing tag as DOMDocument does not handle well.
-				 *
-				 * @var DOMNode $child_node
-				 */
-
-				$new_child_node = $child_node->cloneNode( true );
-				if ( ! $new_child_node instanceof DOMElement ) {
-					continue;
-				}
-
-				$old_child_attributes = AMP_DOM_Utils::get_node_attributes_as_assoc_array( $new_child_node );
-				$new_child_attributes = $this->filter_attributes( $old_child_attributes );
-
-				if ( empty( $new_child_attributes['src'] ) ) {
-					continue;
-				}
-				if ( 'source' !== $new_child_node->tagName ) {
-					continue;
-				}
-
-				// The textContent is invalid for `source` nodes.
-				$new_child_node->textContent = null;
-
-				// Only append source tags with a valid src attribute.
-				$new_node->appendChild( $new_child_node );
-
-			}
-
-			/**
-			 * If the node has at least one valid source, replace the old node with it.
-			 * Otherwise, just remove the node.
-			 *
-			 * @todo: Add a fallback handler.
-			 * @see: https://github.com/ampproject/amphtml/issues/2261
-			 */
-			if ( 0 === $new_node->childNodes->length && empty( $new_attributes['src'] ) ) {
-				$this->remove_invalid_child( $node );
-			} else {
-
-				$layout = isset( $new_attributes['layout'] ) ? $new_attributes['layout'] : false;
-
-				// The width has to be unset / auto in case of fixed-height.
-				if ( 'fixed-height' === $layout ) {
-					$new_node->setAttribute( 'width', 'auto' );
-				}
-
-				$node->parentNode->replaceChild( $new_node, $node );
-			}
-
-			$this->did_convert_elements = true;
-		}
-	}
-
-	/**
-	 * "Filter" HTML attributes for <amp-audio> elements.
-	 *
-	 * @since 0.2
-	 *
-	 * @param string[] $attributes {
-	 *      Attributes.
-	 *
-	 *      @type string $src Audio URL - Empty if HTTPS required per $this->args['require_https_src']
-	 *      @type int $width <audio> attribute - Set to numeric value if px or %
-	 *      @type int $height <audio> attribute - Set to numeric value if px or %
-	 *      @type string $class <audio> attribute - Pass along if found
-	 *      @type bool $loop <audio> attribute - Convert 'false' to empty string ''
-	 *      @type bool $muted <audio> attribute - Convert 'false' to empty string ''
-	 *      @type bool $autoplay <audio> attribute - Convert 'false' to empty string ''
-	 * }
-	 * @return array Returns HTML attributes; removes any not specifically declared above from input.
-	 */
-	private function filter_attributes( $attributes ) {
-		$out = array();
-
-		foreach ( $attributes as $name => $value ) {
-			switch ( $name ) {
-				case 'src':
-					$out[ $name ] = $this->maybe_enforce_https_src( $value );
-					break;
-
-				case 'width':
-				case 'height':
-					$out[ $name ] = $this->sanitize_dimension( $value, $name );
-					break;
-
-				case 'class':
-					$out[ $name ] = $value;
-					break;
-				case 'loop':
-				case 'muted':
-				case 'autoplay':
-					if ( 'false' !== $value ) {
-						$out[ $name ] = '';
-					}
-					break;
-
-				case 'data-amp-layout':
-					$out['layout'] = $value;
-					break;
-
-				case 'data-amp-noloading':
-					$out['noloading'] = $value;
-					break;
-
-				default:
-					break;
-			}
-		}
-
-		return $out;
-	}
-}
diff --git a/includes/sanitizers/class-amp-base-sanitizer.php b/includes/sanitizers/class-amp-base-sanitizer.php
deleted file mode 100644
index 5319a9f7dce..00000000000
--- a/includes/sanitizers/class-amp-base-sanitizer.php
+++ /dev/null
@@ -1,583 +0,0 @@
-<?php
-/**
- * Class AMP_Base_Sanitizer
- *
- * @package AMP
- */
-
-/**
- * Class AMP_Base_Sanitizer
- */
-abstract class AMP_Base_Sanitizer {
-
-	/**
-	 * Value used with the height attribute in an $attributes parameter is empty.
-	 *
-	 * @since 0.3.3
-	 *
-	 * @const int
-	 */
-	const FALLBACK_HEIGHT = 400;
-
-	/**
-	 * Value for <amp-image-lightbox> ID.
-	 *
-	 * @since 1.0
-	 *
-	 * @const string
-	 */
-	const AMP_IMAGE_LIGHTBOX_ID = 'amp-image-lightbox';
-
-	/**
-	 * Placeholder for default args, to be set in child classes.
-	 *
-	 * @since 0.2
-	 *
-	 * @var array
-	 */
-	protected $DEFAULT_ARGS = array();
-
-	/**
-	 * DOM.
-	 *
-	 * @var DOMDocument A standard PHP representation of an HTML document in object form.
-	 *
-	 * @since 0.2
-	 */
-	protected $dom;
-
-	/**
-	 * Array of flags used to control sanitization.
-	 *
-	 * @var array {
-	 *      @type int $content_max_width
-	 *      @type bool $add_placeholder
-	 *      @type bool $use_document_element
-	 *      @type bool $require_https_src
-	 *      @type string[] $amp_allowed_tags
-	 *      @type string[] $amp_globally_allowed_attributes
-	 *      @type string[] $amp_layout_allowed_attributes
-	 *      @type array $amp_allowed_tags
-	 *      @type array $amp_globally_allowed_attributes
-	 *      @type array $amp_layout_allowed_attributes
-	 *      @type array $amp_bind_placeholder_prefix
-	 *      @type bool $allow_dirty_styles
-	 *      @type bool $allow_dirty_scripts
-	 *      @type bool $should_locate_sources
-	 *      @type callable $validation_error_callback
-	 * }
-	 */
-	protected $args;
-
-	/**
-	 * Flag to be set in child class' sanitize() method indicating if the
-	 * HTML contained in the DOMDocument has been sanitized yet or not.
-	 *
-	 * @since 0.2
-	 *
-	 * @var bool
-	 */
-	protected $did_convert_elements = false;
-
-	/**
-	 * The root element used for sanitization. Either html or body.
-	 *
-	 * @var DOMElement
-	 */
-	protected $root_element;
-
-	/**
-	 * Keep track of nodes that should not be removed to prevent duplicated validation errors since sanitization is rejected.
-	 *
-	 * @var array
-	 */
-	private $should_not_removed_nodes = array();
-
-	/**
-	 * AMP_Base_Sanitizer constructor.
-	 *
-	 * @since 0.2
-	 *
-	 * @param DOMDocument $dom Represents the HTML document to sanitize.
-	 * @param array       $args {
-	 *      Args.
-	 *
-	 *      @type int $content_max_width
-	 *      @type bool $add_placeholder
-	 *      @type bool $require_https_src
-	 *      @type string[] $amp_allowed_tags
-	 *      @type string[] $amp_globally_allowed_attributes
-	 *      @type string[] $amp_layout_allowed_attributes
-	 * }
-	 */
-	public function __construct( $dom, $args = array() ) {
-		$this->dom  = $dom;
-		$this->args = array_merge( $this->DEFAULT_ARGS, $args );
-
-		if ( ! empty( $this->args['use_document_element'] ) ) {
-			$this->root_element = $this->dom->documentElement;
-		} else {
-			$this->root_element = $this->dom->getElementsByTagName( 'body' )->item( 0 );
-		}
-	}
-
-	/**
-	 * Add filters to manipulate output during output buffering before the DOM is constructed.
-	 *
-	 * Add actions and filters before the page is rendered so that the sanitizer can fix issues during output buffering.
-	 * This provides an alternative to manipulating the DOM in the sanitize method. This is a static function because
-	 * it is invoked before the class is instantiated, as the DOM is not available yet. This method is only called
-	 * when 'amp' theme support is present. It is conceptually similar to the AMP_Base_Embed_Handler class's register_embed
-	 * method.
-	 *
-	 * @since 1.0
-	 * @see \AMP_Base_Embed_Handler::register_embed()
-	 *
-	 * @param array $args Args.
-	 */
-	public static function add_buffering_hooks( $args = array() ) {}
-
-	/**
-	 * Get mapping of HTML selectors to the AMP component selectors which they may be converted into.
-	 *
-	 * @return array Mapping.
-	 */
-	public function get_selector_conversion_mapping() {
-		return array();
-	}
-
-	/**
-	 * Run logic before any sanitizers are run.
-	 *
-	 * After the sanitizers are instantiated but before calling sanitize on each of them, this
-	 * method is called with list of all the instantiated sanitizers.
-	 *
-	 * @param AMP_Base_Sanitizer[] $sanitizers Sanitizers.
-	 */
-	public function init( $sanitizers ) {}
-
-	/**
-	 * Sanitize the HTML contained in the DOMDocument received by the constructor
-	 */
-	abstract public function sanitize();
-
-	/**
-	 * Return array of values that would be valid as an HTML `script` element.
-	 *
-	 * Array keys are AMP element names and array values are their respective
-	 * Javascript URLs from https://cdn.ampproject.org
-	 *
-	 * @since 0.2
-	 *
-	 * @return string[] Returns component name as array key and JavaScript URL as array value,
-	 *                  respectively. Will return an empty array if sanitization has yet to be run
-	 *                  or if it did not find any HTML elements to convert to AMP equivalents.
-	 */
-	public function get_scripts() {
-		return array();
-	}
-
-	/**
-	 * Return array of values that would be valid as an HTML `style` attribute.
-	 *
-	 * @since 0.4
-	 * @deprecated As of 1.0, use get_stylesheets().
-	 *
-	 * @return array[][] Mapping of CSS selectors to arrays of properties.
-	 */
-	public function get_styles() {
-		return array();
-	}
-
-	/**
-	 * Get stylesheets.
-	 *
-	 * @since 0.7
-	 * @returns array Values are the CSS stylesheets. Keys are MD5 hashes of the stylesheets.
-	 */
-	public function get_stylesheets() {
-		$stylesheets = array();
-
-		foreach ( $this->get_styles() as $selector => $properties ) {
-			$stylesheet = sprintf( '%s { %s }', $selector, join( '; ', $properties ) . ';' );
-
-			$stylesheets[ md5( $stylesheet ) ] = $stylesheet;
-		}
-
-		return $stylesheets;
-	}
-
-	/**
-	 * Get HTML body as DOMElement from DOMDocument received by the constructor.
-	 *
-	 * @deprecated Just reference $root_element instead.
-	 * @return DOMElement The body element.
-	 */
-	protected function get_body_node() {
-		return $this->dom->getElementsByTagName( 'body' )->item( 0 );
-	}
-
-	/**
-	 * Sanitizes a CSS dimension specifier while being sensitive to dimension context.
-	 *
-	 * @param string $value A valid CSS dimension specifier; e.g. 50, 50px, 50%.
-	 * @param string $dimension 'width' or ignored. 'width' only affects $values ending in '%'.
-	 *
-	 * @return float|int|string Returns a numeric dimension value, or an empty string.
-	 */
-	public function sanitize_dimension( $value, $dimension ) {
-
-		// Allows 0 to be used as valid dimension.
-		if ( null === $value ) {
-			return '';
-		}
-
-		// Accepts both integers and floats & prevents negative values.
-		if ( is_numeric( $value ) ) {
-			return max( 0, floatval( $value ) );
-		}
-
-		if ( AMP_String_Utils::endswith( $value, 'px' ) ) {
-			return absint( $value );
-		}
-
-		if ( AMP_String_Utils::endswith( $value, '%' ) ) {
-			if ( 'width' === $dimension && isset( $this->args['content_max_width'] ) ) {
-				$percentage = absint( $value ) / 100;
-				return round( $percentage * $this->args['content_max_width'] );
-			}
-		}
-
-		return '';
-	}
-
-	/**
-	 * Sets the layout, and possibly the 'height' and 'width' attributes.
-	 *
-	 * @param string[] $attributes {
-	 *      Attributes.
-	 *
-	 *      @type int $height
-	 *      @type int $width
-	 *      @type string $sizes
-	 *      @type string $class
-	 *      @type string $layout
-	 * }
-	 * @return array Attributes.
-	 */
-	public function set_layout( $attributes ) {
-		if ( isset( $attributes['layout'] ) && ( 'fill' === $attributes['layout'] || 'flex-item' !== $attributes['layout'] ) ) {
-			return $attributes;
-		}
-		if ( empty( $attributes['height'] ) ) {
-			unset( $attributes['width'] );
-			$attributes['height'] = self::FALLBACK_HEIGHT;
-		}
-		if ( empty( $attributes['width'] ) ) {
-			$attributes['layout'] = 'fixed-height';
-		}
-
-		return $attributes;
-	}
-
-	/**
-	 * Adds or appends key and value to list of attributes
-	 *
-	 * Adds key and value to list of attributes, or if the key already exists in the array
-	 * it concatenates to existing attribute separator by a space or other supplied separator.
-	 *
-	 * @param string[] $attributes {
-	 *      Attributes.
-	 *
-	 *      @type int $height
-	 *      @type int $width
-	 *      @type string $sizes
-	 *      @type string $class
-	 *      @type string $layout
-	 * }
-	 * @param string   $key       Valid associative array index to add.
-	 * @param string   $value     Value to add or append to array indexed at the key.
-	 * @param string   $separator Optional; defaults to space but some other separator if needed.
-	 */
-	public function add_or_append_attribute( &$attributes, $key, $value, $separator = ' ' ) {
-		if ( isset( $attributes[ $key ] ) ) {
-			$attributes[ $key ] = trim( $attributes[ $key ] . $separator . $value );
-		} else {
-			$attributes[ $key ] = $value;
-		}
-	}
-
-	/**
-	 * Decide if we should remove a src attribute if https is required.
-	 *
-	 * If not required, the implementing class may want to try and force https instead.
-	 *
-	 * @param string  $src         URL to convert to HTTPS if forced, or made empty if $args['require_https_src'].
-	 * @param boolean $force_https Force setting of HTTPS if true.
-	 * @return string URL which may have been updated with HTTPS, or may have been made empty.
-	 */
-	public function maybe_enforce_https_src( $src, $force_https = false ) {
-		$protocol = strtok( $src, ':' ); // @todo What about relative URLs? This should use wp_parse_url( $src, PHP_URL_SCHEME )
-		if ( 'https' !== $protocol ) {
-			// Check if https is required.
-			if ( isset( $this->args['require_https_src'] ) && true === $this->args['require_https_src'] ) {
-				// Remove the src. Let the implementing class decide what do from here.
-				$src = '';
-			} elseif ( ( ! isset( $this->args['require_https_src'] ) || false === $this->args['require_https_src'] )
-				&& true === $force_https ) {
-				// Don't remove the src, but force https instead.
-				$src = set_url_scheme( $src, 'https' );
-			}
-		}
-
-		return $src;
-	}
-
-	/**
-	 * Removes an invalid child of a node.
-	 *
-	 * Also, calls the mutation callback for it.
-	 * This tracks all the nodes that were removed.
-	 *
-	 * @since 0.7
-	 *
-	 * @param DOMNode|DOMElement $node             The node to remove.
-	 * @param array              $validation_error Validation error details.
-	 * @return bool Whether the node should have been removed, that is, that the node was sanitized for validity.
-	 */
-	public function remove_invalid_child( $node, $validation_error = array() ) {
-
-		// Prevent double-reporting nodes that are rejected for sanitization.
-		if ( isset( $this->should_not_removed_nodes[ $node->nodeName ] ) && in_array( $node, $this->should_not_removed_nodes[ $node->nodeName ], true ) ) {
-			return false;
-		}
-
-		$should_remove = $this->should_sanitize_validation_error( $validation_error, compact( 'node' ) );
-		if ( $should_remove ) {
-			$node->parentNode->removeChild( $node );
-		} else {
-			$this->should_not_removed_nodes[ $node->nodeName ][] = $node;
-		}
-		return $should_remove;
-	}
-
-	/**
-	 * Removes an invalid attribute of a node.
-	 *
-	 * Also, calls the mutation callback for it.
-	 * This tracks all the attributes that were removed.
-	 *
-	 * @since 0.7
-	 *
-	 * @param DOMElement     $element   The node for which to remove the attribute.
-	 * @param DOMAttr|string $attribute The attribute to remove from the element.
-	 * @param array          $validation_error Validation error details.
-	 * @return bool Whether the node should have been removed, that is, that the node was sanitized for validity.
-	 */
-	public function remove_invalid_attribute( $element, $attribute, $validation_error = array() ) {
-		if ( is_string( $attribute ) ) {
-			$node = $element->getAttributeNode( $attribute );
-		} else {
-			$node = $attribute;
-		}
-		$should_remove = $this->should_sanitize_validation_error( $validation_error, compact( 'node' ) );
-		if ( $should_remove ) {
-			$element->removeAttributeNode( $node );
-		}
-		return $should_remove;
-	}
-
-	/**
-	 * Check whether or not sanitization should occur in response to validation error.
-	 *
-	 * @since 1.0
-	 *
-	 * @param array $validation_error Validation error.
-	 * @param array $data             Data including the node.
-	 * @return bool Whether to sanitize.
-	 */
-	public function should_sanitize_validation_error( $validation_error, $data = array() ) {
-		if ( empty( $this->args['validation_error_callback'] ) || ! is_callable( $this->args['validation_error_callback'] ) ) {
-			return true;
-		}
-		$validation_error = $this->prepare_validation_error( $validation_error, $data );
-		return false !== call_user_func( $this->args['validation_error_callback'], $validation_error, $data );
-	}
-
-	/**
-	 * Prepare validation error.
-	 *
-	 * @param array $error {
-	 *     Error.
-	 *
-	 *     @type string $code Error code.
-	 * }
-	 * @param array $data {
-	 *     Data.
-	 *
-	 *     @type DOMElement|DOMNode $node The removed node.
-	 * }
-	 * @return array Error.
-	 */
-	public function prepare_validation_error( array $error = array(), array $data = array() ) {
-		$node    = null;
-		$matches = null;
-
-		if ( isset( $data['node'] ) && $data['node'] instanceof DOMNode ) {
-			$node = $data['node'];
-
-			$error['node_name'] = $node->nodeName;
-			if ( $node->parentNode ) {
-				$error['parent_name'] = $node->parentNode->nodeName;
-			}
-		}
-
-		if ( $node instanceof DOMElement ) {
-			if ( ! isset( $error['code'] ) ) {
-				$error['code'] = AMP_Validation_Error_Taxonomy::INVALID_ELEMENT_CODE;
-			}
-
-			if ( ! isset( $error['type'] ) ) {
-				$error['type'] = 'script' === $node->nodeName ? AMP_Validation_Error_Taxonomy::JS_ERROR_TYPE : AMP_Validation_Error_Taxonomy::HTML_ELEMENT_ERROR_TYPE;
-			}
-
-			if ( ! isset( $error['node_attributes'] ) ) {
-				$error['node_attributes'] = array();
-				foreach ( $node->attributes as $attribute ) {
-					$error['node_attributes'][ $attribute->nodeName ] = $attribute->nodeValue;
-				}
-			}
-
-			// Capture script contents.
-			if ( 'script' === $node->nodeName && ! $node->hasAttribute( 'src' ) ) {
-				$error['text'] = $node->textContent;
-			}
-
-			// Suppress 'ver' param from enqueued scripts and styles.
-			if ( 'script' === $node->nodeName && isset( $error['node_attributes']['src'] ) && false !== strpos( $error['node_attributes']['src'], 'ver=' ) ) {
-				$error['node_attributes']['src'] = add_query_arg( 'ver', '__normalized__', $error['node_attributes']['src'] );
-			} elseif ( 'link' === $node->nodeName && isset( $error['node_attributes']['href'] ) && false !== strpos( $error['node_attributes']['href'], 'ver=' ) ) {
-				$error['node_attributes']['href'] = add_query_arg( 'ver', '__normalized__', $error['node_attributes']['href'] );
-			}
-		} elseif ( $node instanceof DOMAttr ) {
-			if ( ! isset( $error['code'] ) ) {
-				$error['code'] = AMP_Validation_Error_Taxonomy::INVALID_ATTRIBUTE_CODE;
-			}
-			if ( ! isset( $error['type'] ) ) {
-				// If this is an attribute that begins with on, like onclick, it should be a js_error.
-				$error['type'] = preg_match( '/^on\w+/', $node->nodeName ) ? AMP_Validation_Error_Taxonomy::JS_ERROR_TYPE : AMP_Validation_Error_Taxonomy::HTML_ATTRIBUTE_ERROR_TYPE;
-			}
-			if ( ! isset( $error['element_attributes'] ) ) {
-				$error['element_attributes'] = array();
-				if ( $node->parentNode && $node->parentNode->hasAttributes() ) {
-					foreach ( $node->parentNode->attributes as $attribute ) {
-						$error['element_attributes'][ $attribute->nodeName ] = $attribute->nodeValue;
-					}
-				}
-			}
-		}
-
-		return $error;
-	}
-
-	/**
-	 * Get data-amp-* values from the parent node 'figure' added by editor block.
-	 *
-	 * @param DOMElement $node Base node.
-	 * @return array AMP data array.
-	 */
-	public function get_data_amp_attributes( $node ) {
-		$attributes = array();
-
-		// Editor blocks add 'figure' as the parent node for images. If this node has data-amp-layout then we should add this as the layout attribute.
-		$parent_node = $node->parentNode;
-		if ( 'figure' === $parent_node->tagName ) {
-			$parent_attributes = AMP_DOM_Utils::get_node_attributes_as_assoc_array( $parent_node );
-			if ( isset( $parent_attributes['data-amp-layout'] ) ) {
-				$attributes['layout'] = $parent_attributes['data-amp-layout'];
-			}
-			if ( isset( $parent_attributes['data-amp-noloading'] ) && true === filter_var( $parent_attributes['data-amp-noloading'], FILTER_VALIDATE_BOOLEAN ) ) {
-				$attributes['noloading'] = $parent_attributes['data-amp-noloading'];
-			}
-		}
-
-		return $attributes;
-	}
-
-	/**
-	 * Set AMP attributes.
-	 *
-	 * @param array $attributes Array of attributes.
-	 * @param array $amp_data Array of AMP attributes.
-	 * @return array Updated attributes.
-	 */
-	public function filter_data_amp_attributes( $attributes, $amp_data ) {
-		if ( isset( $amp_data['layout'] ) ) {
-			$attributes['data-amp-layout'] = $amp_data['layout'];
-		}
-		if ( isset( $amp_data['noloading'] ) ) {
-			$attributes['data-amp-noloading'] = '';
-		}
-		return $attributes;
-	}
-
-	/**
-	 * Set attributes to node's parent element according to layout.
-	 *
-	 * @param DOMElement $node Node.
-	 * @param array      $new_attributes Attributes array.
-	 * @param string     $layout Layout.
-	 * @return array New attributes.
-	 */
-	public function filter_attachment_layout_attributes( $node, $new_attributes, $layout ) {
-
-		// The width has to be unset / auto in case of fixed-height.
-		if ( 'fixed-height' === $layout ) {
-			if ( ! isset( $new_attributes['height'] ) ) {
-				$new_attributes['height'] = self::FALLBACK_HEIGHT;
-			}
-			$new_attributes['width'] = 'auto';
-			$node->parentNode->setAttribute( 'style', 'height: ' . $new_attributes['height'] . 'px; width: auto;' );
-
-			// The parent element should have width/height set and position set in case of 'fill'.
-		} elseif ( 'fill' === $layout ) {
-			if ( ! isset( $new_attributes['height'] ) ) {
-				$new_attributes['height'] = self::FALLBACK_HEIGHT;
-			}
-			$node->parentNode->setAttribute( 'style', 'position:relative; width: 100%; height: ' . $new_attributes['height'] . 'px;' );
-			unset( $new_attributes['width'] );
-			unset( $new_attributes['height'] );
-		} elseif ( 'responsive' === $layout ) {
-			$node->parentNode->setAttribute( 'style', 'position:relative; width: 100%; height: auto' );
-		} elseif ( 'fixed' === $layout ) {
-			if ( ! isset( $new_attributes['height'] ) ) {
-				$new_attributes['height'] = self::FALLBACK_HEIGHT;
-			}
-		}
-
-		return $new_attributes;
-	}
-
-	/**
-	 * Add <amp-image-lightbox> element to body tag if it doesn't exist yet.
-	 */
-	public function maybe_add_amp_image_lightbox_node() {
-
-		$nodes = $this->dom->getElementById( self::AMP_IMAGE_LIGHTBOX_ID );
-		if ( null !== $nodes ) {
-			return;
-		}
-
-		$nodes = $this->dom->getElementsByTagName( 'body' );
-		if ( ! $nodes->length ) {
-			return;
-		}
-		$body_node          = $nodes->item( 0 );
-		$amp_image_lightbox = AMP_DOM_Utils::create_node( $this->dom, 'amp-image-lightbox', array(
-			'id'                           => self::AMP_IMAGE_LIGHTBOX_ID,
-			'layout'                       => 'nodisplay',
-			'data-close-button-aria-label' => __( 'Close', 'amp' ),
-		) );
-		$body_node->appendChild( $amp_image_lightbox );
-	}
-}
diff --git a/includes/sanitizers/class-amp-blacklist-sanitizer.php b/includes/sanitizers/class-amp-blacklist-sanitizer.php
deleted file mode 100644
index 1b2eb9a9872..00000000000
--- a/includes/sanitizers/class-amp-blacklist-sanitizer.php
+++ /dev/null
@@ -1,301 +0,0 @@
-<?php
-/**
- * Class AMP_Blacklist_Sanitizer
- *
- * @package AMP
- */
-
-/**
- * Strips blacklisted tags and attributes from content.
- *
- * See following for blacklist:
- *     https://github.com/ampproject/amphtml/blob/master/spec/amp-html-format.md#html-tags
- *
- * @since 0.5 This has been replaced by AMP_Tag_And_Attribute_Sanitizer but is kept around for back-compat.
- * @deprecated
- */
-class AMP_Blacklist_Sanitizer extends AMP_Base_Sanitizer {
-	const PATTERN_REL_WP_ATTACHMENT = '#wp-att-([\d]+)#';
-
-	/**
-	 * Default args.
-	 *
-	 * @var array
-	 */
-	protected $DEFAULT_ARGS = array(
-		'add_blacklisted_protocols' => array(),
-		'add_blacklisted_tags' => array(),
-		'add_blacklisted_attributes' => array(),
-	);
-
-	/**
-	 * Sanitize.
-	 */
-	public function sanitize() {
-		_deprecated_function( __METHOD__, '0.7', 'AMP_Tag_And_Attribute_Sanitizer::sanitize' );
-
-		$blacklisted_tags       = $this->get_blacklisted_tags();
-		$blacklisted_attributes = $this->get_blacklisted_attributes();
-		$blacklisted_protocols  = $this->get_blacklisted_protocols();
-
-		$body = $this->root_element;
-		$this->strip_tags( $body, $blacklisted_tags );
-		$this->strip_attributes_recursive( $body, $blacklisted_attributes, $blacklisted_protocols );
-	}
-
-	/**
-	 * Strip attributes recursively.
-	 *
-	 * @param DOMNode $node DOM Node.
-	 * @param array   $bad_attributes Bad attributes.
-	 * @param array   $bad_protocols  Bad protocols.
-	 */
-	private function strip_attributes_recursive( $node, $bad_attributes, $bad_protocols ) {
-		if ( XML_ELEMENT_NODE !== $node->nodeType ) {
-			return;
-		}
-
-		$node_name = $node->nodeName;
-
-		// Some nodes may contain valid content but are themselves invalid.
-		// Remove the node but preserve the children.
-		if ( 'font' === $node_name ) {
-			$this->replace_node_with_children( $node, $bad_attributes, $bad_protocols );
-			return;
-		} elseif ( 'a' === $node_name && false === $this->validate_a_node( $node ) ) {
-			$this->replace_node_with_children( $node, $bad_attributes, $bad_protocols );
-			return;
-		}
-
-		if ( $node->hasAttributes() ) {
-			$length = $node->attributes->length;
-			for ( $i = $length - 1; $i >= 0; $i-- ) {
-				$attribute      = $node->attributes->item( $i );
-				$attribute_name = strtolower( $attribute->name );
-				if ( in_array( $attribute_name, $bad_attributes, true ) ) {
-					$this->remove_invalid_attribute( $node, $attribute_name );
-					continue;
-				}
-
-				// The on* attributes (like onclick) are a special case.
-				if ( 0 === stripos( $attribute_name, 'on' ) && 'on' !== $attribute_name ) {
-					$this->remove_invalid_attribute( $node, $attribute_name );
-					continue;
-				} elseif ( 'a' === $node_name ) {
-					$this->sanitize_a_attribute( $node, $attribute );
-				}
-			}
-		}
-
-		$length = $node->childNodes->length;
-		for ( $i = $length - 1; $i >= 0; $i-- ) {
-			$child_node = $node->childNodes->item( $i );
-
-			$this->strip_attributes_recursive( $child_node, $bad_attributes, $bad_protocols );
-		}
-	}
-
-	/**
-	 * Strip tags.
-	 *
-	 * @param DOMElement $node      Node.
-	 * @param string[]   $tag_names Tag names.
-	 */
-	private function strip_tags( $node, $tag_names ) {
-		foreach ( $tag_names as $tag_name ) {
-			$elements = $node->getElementsByTagName( $tag_name );
-			$length   = $elements->length;
-			if ( 0 === $length ) {
-				continue;
-			}
-
-			for ( $i = $length - 1; $i >= 0; $i-- ) {
-				$element     = $elements->item( $i );
-				$parent_node = $element->parentNode;
-				$this->remove_invalid_child( $element );
-
-				if ( 'body' !== $parent_node->nodeName && AMP_DOM_Utils::is_node_empty( $parent_node ) ) {
-					$this->remove_invalid_child( $parent_node );
-				}
-			}
-		}
-	}
-
-	/**
-	 * Sanitize attribute.
-	 *
-	 * @param DOMElement $node      Node.
-	 * @param DOMAttr    $attribute Attribute.
-	 */
-	private function sanitize_a_attribute( $node, $attribute ) {
-		$attribute_name = strtolower( $attribute->name );
-
-		if ( 'rel' === $attribute_name ) {
-			$old_value = $attribute->value;
-			$new_value = trim( preg_replace( self::PATTERN_REL_WP_ATTACHMENT, '', $old_value ) );
-			if ( empty( $new_value ) ) {
-				$this->remove_invalid_attribute( $node, $attribute_name );
-			} elseif ( $old_value !== $new_value ) {
-				$node->setAttribute( $attribute_name, $new_value );
-			}
-		} elseif ( 'rev' === $attribute_name ) {
-			// rev removed from HTML5 spec, which was used by Jetpack Markdown.
-			$this->remove_invalid_attribute( $node, $attribute_name );
-		} elseif ( 'target' === $attribute_name ) {
-			// _blank is the only allowed value and it must be lowercase.
-			// replace _new with _blank and others should simply be removed.
-			$old_value = strtolower( $attribute->value );
-			if ( '_blank' === $old_value || '_new' === $old_value ) {
-				// _new is not allowed; swap with _blank
-				$node->setAttribute( $attribute_name, '_blank' );
-			} else {
-				// Only _blank is allowed.
-				$this->remove_invalid_attribute( $node, $attribute_name );
-			}
-		}
-	}
-
-	/**
-	 * Validate node.
-	 *
-	 * @param DOMElement $node Node.
-	 * @return bool
-	 */
-	private function validate_a_node( $node ) {
-		// Get the href attribute.
-		$href = $node->getAttribute( 'href' );
-
-		if ( empty( $href ) ) {
-			/*
-			 * If no href, check that a is an anchor or not.
-			 * We don't need to validate anchors any further.
-			 */
-			return $node->hasAttribute( 'name' ) || $node->hasAttribute( 'id' );
-		}
-
-		// If this is an anchor link, just return true.
-		if ( 0 === strpos( $href, '#' ) ) {
-			return true;
-		}
-
-		// If the href starts with a '/', append the home_url to it for validation purposes.
-		if ( 0 === stripos( $href, '/' ) ) {
-			$href = untrailingslashit( get_home_url() ) . $href;
-		}
-
-		$valid_protocols   = array( 'http', 'https', 'mailto', 'sms', 'tel', 'viber', 'whatsapp' );
-		$special_protocols = array( 'tel', 'sms' ); // These ones don't valid with `filter_var+FILTER_VALIDATE_URL`.
-		$protocol          = strtok( $href, ':' );
-
-		if ( false === filter_var( $href, FILTER_VALIDATE_URL )
-			&& ! in_array( $protocol, $special_protocols, true ) ) {
-			return false;
-		}
-
-		if ( ! in_array( $protocol, $valid_protocols, true ) ) {
-			return false;
-		}
-
-		return true;
-	}
-
-	/**
-	 * Replace node with children.
-	 *
-	 * @param DOMElement $node           Node.
-	 * @param array      $bad_attributes Bad attributes.
-	 * @param array      $bad_protocols  Bad protocols.
-	 */
-	private function replace_node_with_children( $node, $bad_attributes, $bad_protocols ) {
-		// If the node has children and also has a parent node,
-		// clone and re-add all the children just before current node.
-		if ( $node->hasChildNodes() && $node->parentNode ) {
-			foreach ( $node->childNodes as $child_node ) {
-				$new_child = $child_node->cloneNode( true );
-				$this->strip_attributes_recursive( $new_child, $bad_attributes, $bad_protocols );
-				$node->parentNode->insertBefore( $new_child, $node );
-			}
-		}
-
-		// Remove the node from the parent, if defined.
-		if ( $node->parentNode ) {
-			$this->remove_invalid_child( $node );
-		}
-	}
-
-	/**
-	 * Merge defaults with args.
-	 *
-	 * @param string $key    Key.
-	 * @param array  $values Values.
-	 * @return array Merged args.
-	 */
-	private function merge_defaults_with_args( $key, $values ) {
-		// Merge default values with user specified args.
-		if ( ! empty( $this->args[ $key ] )
-			&& is_array( $this->args[ $key ] ) ) {
-			$values = array_merge( $values, $this->args[ $key ] );
-		}
-
-		return $values;
-	}
-
-	/**
-	 * Get blacklisted protocols.
-	 *
-	 * @return array Protocols.
-	 */
-	private function get_blacklisted_protocols() {
-		return $this->merge_defaults_with_args( 'add_blacklisted_protocols', array(
-			'javascript',
-		) );
-	}
-
-	/**
-	 * Get blacklisted tags.
-	 *
-	 * @return array Tags.
-	 */
-	private function get_blacklisted_tags() {
-		return $this->merge_defaults_with_args( 'add_blacklisted_tags', array(
-			'script',
-			'noscript',
-			'style',
-			'frame',
-			'frameset',
-			'object',
-			'param',
-			'applet',
-			'form',
-			'label',
-			'input',
-			'textarea',
-			'select',
-			'option',
-			'link',
-			'picture',
-
-			// Sanitizers run after embed handlers, so if anything wasn't matched, it needs to be removed.
-			'embed',
-			'embedvideo',
-
-			// Other weird ones.
-			'comments-count',
-		) );
-	}
-
-	/**
-	 * Get blacklisted attributes.
-	 *
-	 * @return array Attributes.
-	 */
-	private function get_blacklisted_attributes() {
-		return $this->merge_defaults_with_args( 'add_blacklisted_attributes', array(
-			'style',
-			'size',
-			'clear',
-			'align',
-			'valign',
-		) );
-	}
-}
diff --git a/includes/sanitizers/class-amp-block-sanitizer.php b/includes/sanitizers/class-amp-block-sanitizer.php
deleted file mode 100644
index 1cf0c0eff89..00000000000
--- a/includes/sanitizers/class-amp-block-sanitizer.php
+++ /dev/null
@@ -1,133 +0,0 @@
-<?php
-/**
- * Class AMP_Block_Sanitizer.
- *
- * @package AMP
- */
-
-/**
- * Class AMP_Block_Sanitizer
- *
- * Modifies elements created as blocks to match the blocks' AMP-specific configuration.
- */
-class AMP_Block_Sanitizer extends AMP_Base_Sanitizer {
-
-	/**
-	 * Tag.
-	 *
-	 * @var string Figure tag to identify wrapper around AMP elements.
-	 * @since 1.0
-	 */
-	public static $tag = 'figure';
-
-	/**
-	 * Sanitize the AMP elements contained by <figure> element where necessary.
-	 *
-	 * @since 0.2
-	 */
-	public function sanitize() {
-		$nodes     = $this->dom->getElementsByTagName( self::$tag );
-		$num_nodes = $nodes->length;
-		if ( 0 === $num_nodes ) {
-			return;
-		}
-
-		for ( $i = $num_nodes - 1; $i >= 0; $i-- ) {
-			$node = $nodes->item( $i );
-
-			// We're looking for <figure> elements that have one child node only.
-			if ( 1 !== count( $node->childNodes ) ) {
-				continue;
-			}
-
-			$attributes = AMP_DOM_Utils::get_node_attributes_as_assoc_array( $node );
-
-			// We are only looking for <figure> elements which have wp-block-embed as class.
-			if ( ! isset( $attributes['class'] ) || false === strpos( $attributes['class'], 'wp-block-embed' ) ) {
-				continue;
-			}
-
-			// We are looking for <figure> elements with layout attribute only.
-			if (
-				! isset( $attributes['data-amp-layout'] ) &&
-				! isset( $attributes['data-amp-noloading'] ) &&
-				! isset( $attributes['data-amp-lightbox'] )
-			) {
-				continue;
-			}
-
-			$amp_el_found = false;
-
-			foreach ( $node->childNodes as $child_node ) {
-
-				// We are looking for child elements which start with 'amp-'.
-				if ( 0 !== strpos( $child_node->tagName, 'amp-' ) ) {
-					continue;
-				}
-				$amp_el_found = true;
-
-				$this->set_attributes( $child_node, $node, $attributes );
-			}
-
-			if ( false === $amp_el_found ) {
-				continue;
-			}
-			$this->did_convert_elements = true;
-		}
-	}
-
-	/**
-	 * Sets necessary attributes to both parent and AMP element node.
-	 *
-	 * @param DOMNode $node AMP element node.
-	 * @param DOMNode $parent_node <figure> node.
-	 * @param array   $attributes Current attributes of the AMP element.
-	 */
-	protected function set_attributes( $node, $parent_node, $attributes ) {
-
-		if ( isset( $attributes['data-amp-layout'] ) ) {
-			$node->setAttribute( 'layout', $attributes['data-amp-layout'] );
-		}
-		if ( isset( $attributes['data-amp-noloading'] ) && true === filter_var( $attributes['data-amp-noloading'], FILTER_VALIDATE_BOOLEAN ) ) {
-			$node->setAttribute( 'noloading', '' );
-		}
-
-		$layout = $node->getAttribute( 'layout' );
-
-		// The width has to be unset / auto in case of fixed-height.
-		if ( 'fixed-height' === $layout ) {
-			if ( ! isset( $attributes['height'] ) ) {
-				$node->setAttribute( 'height', self::FALLBACK_HEIGHT );
-			}
-			$node->setAttribute( 'width', 'auto' );
-
-			$height = $node->getAttribute( 'height' );
-			if ( is_numeric( $height ) ) {
-				$height .= 'px';
-			}
-			$parent_node->setAttribute( 'style', "height: $height; width: auto;" );
-
-			// The parent element should have width/height set and position set in case of 'fill'.
-		} elseif ( 'fill' === $layout ) {
-			if ( ! isset( $attributes['height'] ) ) {
-				$attributes['height'] = self::FALLBACK_HEIGHT;
-			}
-			$parent_node->setAttribute( 'style', 'position:relative; width: 100%; height: ' . $attributes['height'] . 'px;' );
-			$node->removeAttribute( 'width' );
-			$node->removeAttribute( 'height' );
-		} elseif ( 'responsive' === $layout ) {
-			$parent_node->setAttribute( 'style', 'position:relative; width: 100%; height: auto' );
-		} elseif ( 'fixed' === $layout ) {
-			if ( ! isset( $attributes['height'] ) ) {
-				$node->setAttribute( 'height', self::FALLBACK_HEIGHT );
-			}
-		}
-
-		// Set the fallback layout in case needed.
-		$attributes = AMP_DOM_Utils::get_node_attributes_as_assoc_array( $node );
-		$attributes = $this->set_layout( $attributes );
-		if ( $layout !== $attributes['layout'] ) {
-			$node->setAttribute( 'layout', $attributes['layout'] );
-		}
-	}
-}
diff --git a/includes/sanitizers/class-amp-comments-sanitizer.php b/includes/sanitizers/class-amp-comments-sanitizer.php
deleted file mode 100644
index 05b3844723b..00000000000
--- a/includes/sanitizers/class-amp-comments-sanitizer.php
+++ /dev/null
@@ -1,156 +0,0 @@
-<?php
-/**
- * Class AMP_Comments_Sanitizer.
- *
- * @package AMP
- */
-
-/**
- * Class AMP_Comments_Sanitizer
- *
- * Strips and corrects attributes in forms.
- */
-class AMP_Comments_Sanitizer extends AMP_Base_Sanitizer {
-
-	/**
-	 * Pre-process the comment form and comment list for AMP.
-	 *
-	 * @since 0.7
-	 */
-	public function sanitize() {
-
-		foreach ( $this->dom->getElementsByTagName( 'form' ) as $comment_form ) {
-			/**
-			 * Comment form.
-			 *
-			 * @var DOMElement $comment_form
-			 */
-			$action = $comment_form->getAttribute( 'action-xhr' );
-			if ( ! $action ) {
-				$action = $comment_form->getAttribute( 'action' );
-			}
-			$action_path = wp_parse_url( $action, PHP_URL_PATH );
-			if ( preg_match( '#/wp-comments-post\.php$#', $action_path ) ) {
-				$this->process_comment_form( $comment_form );
-			}
-		}
-	}
-
-	/**
-	 * Comment form.
-	 *
-	 * @param DOMElement $comment_form Comment form.
-	 */
-	protected function process_comment_form( $comment_form ) {
-		/**
-		 * Element.
-		 *
-		 * @var DOMElement $element
-		 */
-
-		/**
-		 * Named input elements.
-		 *
-		 * @var DOMElement[][] $form_fields
-		 */
-		$form_fields = array();
-		foreach ( $comment_form->getElementsByTagName( 'input' ) as $element ) {
-			$name = $element->getAttribute( 'name' );
-			if ( $name ) {
-				$form_fields[ $name ][] = $element;
-			}
-		}
-		foreach ( $comment_form->getElementsByTagName( 'textarea' ) as $element ) {
-			$name = $element->getAttribute( 'name' );
-			if ( $name ) {
-				$form_fields[ $name ][] = $element;
-			}
-		}
-
-		if ( empty( $form_fields['comment_post_ID'] ) ) {
-			return;
-		}
-		$post_id  = (int) $form_fields['comment_post_ID'][0]->getAttribute( 'value' );
-		$state_id = AMP_Theme_Support::get_comment_form_state_id( $post_id );
-
-		$form_state = array(
-			'values'      => array(),
-			'submitting'  => false,
-			'replyToName' => '',
-		);
-
-		if ( ! empty( $form_fields['comment_parent'] ) ) {
-			$comment_id = (int) $form_fields['comment_parent'][0]->getAttribute( 'value' );
-			if ( $comment_id ) {
-				$reply_comment = get_comment( $comment_id );
-				if ( $reply_comment ) {
-					$form_state['replyToName'] = $reply_comment->comment_author;
-				}
-			}
-		}
-
-		$amp_bind_attr_format = AMP_DOM_Utils::get_amp_bind_placeholder_prefix() . '%s';
-		foreach ( $form_fields as $name => $form_field ) {
-			foreach ( $form_field as $element ) {
-
-				// @todo Radio and checkbox inputs are not supported yet.
-				if ( in_array( strtolower( $element->getAttribute( 'type' ) ), array( 'checkbox', 'radio' ), true ) ) {
-					continue;
-				}
-
-				$element->setAttribute( sprintf( $amp_bind_attr_format, 'disabled' ), "$state_id.submitting" );
-
-				if ( 'textarea' === strtolower( $element->nodeName ) ) {
-					$form_state['values'][ $name ] = $element->textContent;
-					$element->setAttribute( sprintf( $amp_bind_attr_format, 'text' ), "$state_id.values.$name" );
-				} else {
-					$form_state['values'][ $name ] = $element->hasAttribute( 'value' ) ? $element->getAttribute( 'value' ) : '';
-					$element->setAttribute( sprintf( $amp_bind_attr_format, 'value' ), "$state_id.values.$name" );
-				}
-
-				// Update the state in response to changing the input.
-				$element->setAttribute( 'on', sprintf(
-					'change:AMP.setState( { %s: { values: { %s: event.value } } } )',
-					$state_id,
-					wp_json_encode( $name )
-				) );
-			}
-		}
-
-		// Add amp-state to the document.
-		$amp_state = $this->dom->createElement( 'amp-state' );
-		$amp_state->setAttribute( 'id', $state_id );
-		$script = $this->dom->createElement( 'script' );
-		$script->setAttribute( 'type', 'application/json' );
-		$amp_state->appendChild( $script );
-		$script->appendChild( $this->dom->createTextNode( wp_json_encode( $form_state ) ) );
-		$comment_form->insertBefore( $amp_state, $comment_form->firstChild );
-
-		// Update state when submitting form.
-		$form_reset_state = $form_state;
-		unset(
-			$form_reset_state['values']['author'],
-			$form_reset_state['values']['email'],
-			$form_reset_state['values']['url']
-		);
-		$on = array(
-			// Disable the form when submitting.
-			sprintf(
-				'submit:AMP.setState( { %s: { submitting: true } } )',
-				wp_json_encode( $state_id )
-			),
-			// Re-enable the form fields when the submission fails.
-			sprintf(
-				'submit-error:AMP.setState( { %s: { submitting: false } } )',
-				wp_json_encode( $state_id )
-			),
-			// Reset the form to its initial state (with enabled form fields), except for the author, email, and url.
-			sprintf(
-				'submit-success:AMP.setState( { %s: %s } )',
-				$state_id,
-				wp_json_encode( $form_reset_state )
-			),
-		);
-		$comment_form->setAttribute( 'on', implode( ';', $on ) );
-	}
-}
diff --git a/includes/sanitizers/class-amp-core-theme-sanitizer.php b/includes/sanitizers/class-amp-core-theme-sanitizer.php
deleted file mode 100644
index 2e22faf4882..00000000000
--- a/includes/sanitizers/class-amp-core-theme-sanitizer.php
+++ /dev/null
@@ -1,1107 +0,0 @@
-<?php
-/**
- * Class AMP_Core_Theme_Sanitizer.
- *
- * @package AMP
- * @since 1.0
- */
-
-/**
- * Class AMP_Core_Theme_Sanitizer
- *
- * Fixes up common issues in core themes and others.
- *
- * @see AMP_Validation_Error_Taxonomy::accept_core_theme_validation_errors()
- * @since 1.0
- */
-class AMP_Core_Theme_Sanitizer extends AMP_Base_Sanitizer {
-
-	/**
-	 * Array of flags used to control sanitization.
-	 *
-	 * @since 1.0
-	 * @var array {
-	 *      @type string $stylesheet     Stylesheet slug.
-	 *      @type string $template       Template slug.
-	 *      @type array  $theme_features List of theme features that need to be applied. Features are method names,
-	 * }
-	 */
-	protected $args;
-
-	/**
-	 * Body element.
-	 *
-	 * @since 1.0
-	 * @var DOMElement
-	 */
-	protected $body;
-
-	/**
-	 * XPath.
-	 *
-	 * @since 1.0
-	 * @var DOMXPath
-	 */
-	protected $xpath;
-
-	/**
-	 * Config for features needed by themes.
-	 *
-	 * @since 1.0
-	 * @var array
-	 */
-	protected static $theme_features = array(
-		// Twenty Nineteen.
-		'twentynineteen'  => array(
-			'dequeue_scripts'                             => array(
-				'twentynineteen-skip-link-focus-fix', // This is part of AMP. See <https://github.com/ampproject/amphtml/issues/18671>.
-				'twentynineteen-priority-menu',
-				'twentynineteen-touch-navigation', // @todo There could be an AMP implementation of this, similar to what is implemented on ampproject.org.
-			),
-			'remove_actions'                              => array(
-				'wp_print_footer_scripts' => array(
-					'twentynineteen_skip_link_focus_fix', // See <https://github.com/WordPress/twentynineteen/pull/47>.
-				),
-			),
-			'add_twentynineteen_masthead_styles'          => array(),
-			'add_twentynineteen_image_styles'             => array(),
-			'remove_twentynineteen_thumbnail_image_sizes' => array(),
-
-		),
-
-		// Twenty Seventeen.
-		'twentyseventeen' => array(
-			// @todo Try to implement belowEntryMetaClass().
-			'dequeue_scripts'                     => array(
-				'twentyseventeen-html5', // Only relevant for IE<9.
-				'twentyseventeen-global', // There are somethings not yet implemented in AMP. See todos below.
-				'jquery-scrollto', // Implemented via add_smooth_scrolling().
-				'twentyseventeen-navigation', // Handled by add_nav_menu_styles, add_nav_menu_toggle, add_nav_sub_menu_buttons.
-				'twentyseventeen-skip-link-focus-fix', // Only needed by IE11 and when admin bar is present.
-			),
-			'remove_actions'                      => array(
-				'wp_head' => array(
-					'twentyseventeen_javascript_detection', // AMP is essentially no-js, with any interactively added explicitly via amp-bind.
-				),
-			),
-			'force_svg_support'                   => array(),
-			'force_fixed_background_support'      => array(),
-			'add_twentyseventeen_masthead_styles' => array(),
-			'add_twentyseventeen_sticky_nav_menu' => array(),
-			'add_has_header_video_body_class'     => array(),
-			'add_nav_menu_styles'                 => array(),
-			'add_nav_menu_toggle'                 => array(),
-			'add_nav_sub_menu_buttons'            => array(),
-			'add_smooth_scrolling'                => array(
-				'//header[@id = "masthead"]//a[ contains( @class, "menu-scroll-down" ) ]',
-			),
-			'set_twentyseventeen_quotes_icon'     => array(),
-			'add_twentyseventeen_attachment_image_attributes' => array(),
-		),
-
-		// Twenty Sixteen.
-		'twentysixteen'   => array(
-			// @todo Figure out an AMP solution for onResizeARIA().
-			// @todo Try to implement belowEntryMetaClass().
-			'dequeue_scripts'          => array(
-				'twentysixteen-script',
-				'twentysixteen-html5', // Only relevant for IE<9.
-				'twentysixteen-keyboard-image-navigation', // AMP does not yet allow for listening to keydown events.
-				'twentysixteen-skip-link-focus-fix', // Only needed by IE11 and when admin bar is present.
-			),
-			'remove_actions'           => array(
-				'wp_head' => array(
-					'twentysixteen_javascript_detection', // AMP is essentially no-js, with any interactively added explicitly via amp-bind.
-				),
-			),
-			'add_nav_menu_styles'      => array(),
-			'add_nav_menu_toggle'      => array(),
-			'add_nav_sub_menu_buttons' => array(),
-		),
-
-		// Twenty Fifteen.
-		'twentyfifteen'   => array(
-			// @todo Figure out an AMP solution for onResizeARIA().
-			'dequeue_scripts'          => array(
-				'twentyfifteen-script',
-				'twentyfifteen-keyboard-image-navigation', // AMP does not yet allow for listening to keydown events.
-				'twentyfifteen-skip-link-focus-fix', // Only needed by IE11 and when admin bar is present.
-			),
-			'remove_actions'           => array(
-				'wp_head' => array(
-					'twentyfifteen_javascript_detection', // AMP is essentially no-js, with any interactively added explicitly via amp-bind.
-				),
-			),
-			'add_nav_menu_styles'      => array(),
-			'add_nav_menu_toggle'      => array(),
-			'add_nav_sub_menu_buttons' => array(),
-		),
-	);
-
-	/**
-	 * Get list of supported core themes.
-	 *
-	 * @since 1.0
-	 *
-	 * @return string[] Slugs for supported themes.
-	 */
-	public static function get_supported_themes() {
-		return array_keys( self::$theme_features );
-	}
-
-	/**
-	 * Get the acceptable validation errors.
-	 *
-	 * @since 1.0
-	 *
-	 * @param string $template Template.
-	 * @return array Acceptable errors.
-	 */
-	public static function get_acceptable_errors( $template ) {
-		switch ( $template ) {
-			case 'twentyfifteen':
-				return array(
-					'removed_unused_css_rules' => true,
-					'illegal_css_at_rule'      => array(
-						array(
-							'at_rule'         => 'viewport',
-							'node_attributes' => array(
-								'id' => 'twentyfifteen-style-css',
-							),
-						),
-						array(
-							'at_rule'         => '-ms-viewport',
-							'node_attributes' => array(
-								'id' => 'twentyfifteen-style-css',
-							),
-						),
-					),
-				);
-			case 'twentysixteen':
-				return array(
-					'removed_unused_css_rules' => true,
-					'illegal_css_at_rule'      => array(
-						array(
-							'at_rule'         => 'viewport',
-							'node_attributes' => array(
-								'id' => 'twentysixteen-style-css',
-							),
-						),
-						array(
-							'at_rule'         => '-ms-viewport',
-							'node_attributes' => array(
-								'id' => 'twentysixteen-style-css',
-							),
-						),
-					),
-				);
-			case 'twentyseventeen':
-				return array(
-					'removed_unused_css_rules' => true,
-				);
-		}
-		return array();
-	}
-
-	/**
-	 * Get theme config.
-	 *
-	 * @since 1.0
-	 *
-	 * @param string $theme Theme slug.
-	 * @return array Class names.
-	 */
-	protected static function get_theme_config( $theme ) {
-		// phpcs:disable WordPress.WP.I18n.TextDomainMismatch
-		$config = array(
-			'sub_menu_button_class' => 'dropdown-toggle',
-		);
-		switch ( $theme ) {
-			case 'twentyfifteen':
-				return array_merge(
-					$config,
-					array(
-						'nav_container_id'             => 'secondary',
-						'nav_container_toggle_class'   => 'toggled-on',
-						'menu_button_class'            => 'secondary-toggle',
-						'menu_button_xpath'            => '//header[ @id = "masthead" ]//button[ contains( @class, "secondary-toggle" ) ]',
-						'menu_button_toggle_class'     => 'toggled-on',
-						'sub_menu_button_toggle_class' => 'toggle-on',
-						'expand_text '                 => __( 'expand child menu', 'twentyfifteen' ),
-						'collapse_text'                => __( 'collapse child menu', 'twentyfifteen' ),
-					)
-				);
-
-			case 'twentysixteen':
-				return array_merge(
-					$config,
-					array(
-						'nav_container_id'             => 'site-header-menu',
-						'nav_container_toggle_class'   => 'toggled-on',
-						'menu_button_class'            => 'menu-toggle',
-						'menu_button_xpath'            => '//header[@id = "masthead"]//button[ @id = "menu-toggle" ]',
-						'menu_button_toggle_class'     => 'toggled-on',
-						'sub_menu_button_toggle_class' => 'toggled-on',
-						'expand_text '                 => __( 'expand child menu', 'twentysixteen' ),
-						'collapse_text'                => __( 'collapse child menu', 'twentysixteen' ),
-					)
-				);
-
-			case 'twentyseventeen':
-			default:
-				return array_merge(
-					$config,
-					array(
-						'nav_container_id'             => 'site-navigation',
-						'nav_container_toggle_class'   => 'toggled-on',
-						'menu_button_class'            => 'menu-toggle',
-						'menu_button_xpath'            => '//nav[@id = "site-navigation"]//button[ contains( @class, "menu-toggle" ) ]',
-						'menu_button_toggle_class'     => 'toggled-on',
-						'sub_menu_button_toggle_class' => 'toggled-on',
-						'expand_text '                 => __( 'expand child menu', 'twentyseventeen' ),
-						'collapse_text'                => __( 'collapse child menu', 'twentyseventeen' ),
-					)
-				);
-		}
-		// phpcs:enable WordPress.WP.I18n.TextDomainMismatch
-	}
-
-	/**
-	 * Find theme features for core theme.
-	 *
-	 * @since 1.0
-	 *
-	 * @param array $args   Args.
-	 * @param bool  $static Static. that is, whether should run during output buffering.
-	 * @return array Theme features.
-	 */
-	protected static function get_theme_features( $args, $static = false ) {
-		$theme_features   = array();
-		$theme_candidates = wp_array_slice_assoc( $args, array( 'stylesheet', 'template' ) );
-		foreach ( $theme_candidates as $theme_candidate ) {
-			if ( isset( self::$theme_features[ $theme_candidate ] ) ) {
-				$theme_features = self::$theme_features[ $theme_candidate ];
-				break;
-			}
-		}
-
-		// Allow specific theme features to be requested even if the theme is not in core.
-		if ( isset( $args['theme_features'] ) ) {
-			$theme_features = array_merge( $args['theme_features'], $theme_features );
-		}
-
-		$final_theme_features = array();
-		foreach ( $theme_features as $theme_feature => $feature_args ) {
-			if ( ! method_exists( __CLASS__, $theme_feature ) ) {
-				continue;
-			}
-			try {
-				$reflection = new ReflectionMethod( __CLASS__, $theme_feature );
-				if ( $reflection->isStatic() === $static ) {
-					$final_theme_features[ $theme_feature ] = $feature_args;
-				}
-			} catch ( Exception $e ) {
-				unset( $e );
-			}
-		}
-		return $final_theme_features;
-	}
-
-	/**
-	 * Add filters to manipulate output during output buffering before the DOM is constructed.
-	 *
-	 * @since 1.0
-	 *
-	 * @param array $args Args.
-	 */
-	public static function add_buffering_hooks( $args = array() ) {
-		$theme_features = self::get_theme_features( $args, true );
-		foreach ( $theme_features as $theme_feature => $feature_args ) {
-			if ( method_exists( __CLASS__, $theme_feature ) ) {
-				call_user_func( array( __CLASS__, $theme_feature ), $feature_args );
-			}
-		}
-	}
-
-	/**
-	 * Add filter to output the quote icons in front of the article content.
-	 *
-	 * This is only used in Twenty Seventeen.
-	 *
-	 * @since 1.0
-	 * @link https://github.com/WordPress/wordpress-develop/blob/f4580c122b7d0d2d66d22f806c6fe6e11023c6f0/src/wp-content/themes/twentyseventeen/assets/js/global.js#L105-L108
-	 */
-	public static function set_twentyseventeen_quotes_icon() {
-		add_filter( 'the_content', function ( $content ) {
-
-			// Why isn't Twenty Seventeen doing this to begin with? Why is it using JS to add the quote icon?
-			if ( function_exists( 'twentyseventeen_get_svg' ) && 'quote' === get_post_format() ) {
-				$icon    = twentyseventeen_get_svg( array( 'icon' => 'quote-right' ) );
-				$content = preg_replace( '#(<blockquote.*?>)#s', '$1' . $icon, $content );
-			}
-
-			return $content;
-		} );
-	}
-
-	/**
-	 * Remove the sizes attribute from thumbnail images in Twenty Nineteen.
-	 *
-	 * The AMP runtime sets an inline style on an <amp-img> based on the sizes attribute if it's present.
-	 * For example, <amp-img style="width:calc(50vw)">.
-	 * Removing the 'sizes' attribute isn't ideal, but it looks like it's not possible to override that inline style.
-	 *
-	 * @todo: remove when this is resolved: https://github.com/ampproject/amphtml/issues/17053
-	 * @since 1.0
-	 */
-	public static function remove_twentynineteen_thumbnail_image_sizes() {
-		add_filter( 'wp_get_attachment_image_attributes', function( $attr ) {
-			if ( isset( $attr['class'] ) && false !== strpos( $attr['class'], 'attachment-post-thumbnail' ) ) {
-				unset( $attr['sizes'] );
-			}
-
-			return $attr;
-		}, 11 );
-	}
-
-	/**
-	 * Add filter to adjust the attachment image attributes to ensure attachment pages have a consistent <amp-img> rendering.
-	 *
-	 * This is only used in Twenty Seventeen.
-	 *
-	 * @since 1.0
-	 * @link https://github.com/WordPress/wordpress-develop/blob/ddc8f803c6e99118998191fd2ea24124feb53659/src/wp-content/themes/twentyseventeen/functions.php#L545:L554
-	 */
-	public static function add_twentyseventeen_attachment_image_attributes() {
-		add_filter( 'wp_get_attachment_image_attributes', function ( $attr, $attachment, $size ) {
-			if ( isset( $attr['class'] ) && 'custom-logo' === $attr['class'] ) {
-				unset( $attr['sizes'] );
-			} elseif ( is_attachment() ) {
-				$sizes = wp_get_attachment_image_sizes( $attachment->ID, $size );
-				if ( false !== $sizes ) {
-					$attr['sizes'] = $sizes;
-				}
-			}
-			return $attr;
-		}, 11, 3 );
-
-		/*
-		 * The max-height of the `.custom-logo-link img` is defined as being 80px, unless
-		 * there is header media in which case it is 200px. Issues related to vertically-squashed
-		 * images can be avoided if we just make sure that the image has this height to begin with.
-		 */
-		add_filter( 'get_custom_logo', function( $html ) {
-			$src = wp_get_attachment_image_src( get_theme_mod( 'custom_logo' ), 'full' );
-			if ( ! $src ) {
-				return $html;
-			}
-
-			if ( 'blank' === get_header_textcolor() && has_custom_header() ) {
-				$height = 200;
-			} else {
-				$height = 80;
-			}
-			$width = $height * ( $src[1] / $src[2] ); // Note that float values are allowed.
-
-			$html = preg_replace( '/(?<=width=")\d+(?=")/', $width, $html );
-			$html = preg_replace( '/(?<=height=")\d+(?=")/', $height, $html );
-			return $html;
-		} );
-	}
-
-	/**
-	 * Fix up core themes to do things in the AMP way.
-	 *
-	 * @since 1.0
-	 */
-	public function sanitize() {
-		$this->body = $this->dom->getElementsByTagName( 'body' )->item( 0 );
-		if ( ! $this->body ) {
-			return;
-		}
-
-		$this->xpath = new DOMXPath( $this->dom );
-
-		$theme_features = self::get_theme_features( $this->args, false );
-		foreach ( $theme_features as $theme_feature => $feature_args ) {
-			if ( method_exists( $this, $theme_feature ) ) {
-				call_user_func( array( $this, $theme_feature ), $feature_args );
-			}
-		}
-	}
-
-	/**
-	 * Dequeue scripts.
-	 *
-	 * @since 1.0
-	 *
-	 * @param string[] $handles Handles, where each item value is the script handle.
-	 */
-	public static function dequeue_scripts( $handles = array() ) {
-		add_action( 'wp_enqueue_scripts', function() use ( $handles ) {
-			foreach ( $handles as $handle ) {
-				wp_dequeue_script( $handle );
-			}
-		}, PHP_INT_MAX );
-	}
-
-	/**
-	 * Remove actions.
-	 *
-	 * @since 1.0
-	 *
-	 * @param array $actions Actions, with action name as key and value being callback.
-	 */
-	public static function remove_actions( $actions = array() ) {
-		foreach ( $actions as $action => $callbacks ) {
-			foreach ( $callbacks as $callback ) {
-				$priority = has_action( $action, $callback );
-				if ( false !== $priority ) {
-					remove_action( $action, $callback, $priority );
-				}
-			}
-		}
-	}
-
-	/**
-	 * Add smooth scrolling from link to target element.
-	 *
-	 * @since 1.0
-	 *
-	 * @param string[] $link_xpaths XPath queries to the links that should smooth scroll.
-	 */
-	public function add_smooth_scrolling( $link_xpaths ) {
-		foreach ( $link_xpaths as $link_xpath ) {
-			foreach ( $this->xpath->query( $link_xpath ) as $link ) {
-				if ( $link instanceof DOMElement && preg_match( '/#(.+)/', $link->getAttribute( 'href' ), $matches ) ) {
-					$link->setAttribute( 'on', sprintf( 'tap:%s.scrollTo(duration=600)', $matches[1] ) );
-				}
-			}
-		}
-	}
-
-	/**
-	 * Force SVG support, replacing no-svg class name with svg class name.
-	 *
-	 * @since 1.0
-	 *
-	 * @link https://github.com/WordPress/wordpress-develop/blob/1af1f65a21a1a697fb5f33027497f9e5ae638453/src/wp-content/themes/twentyseventeen/assets/js/global.js#L211-L213
-	 * @link https://caniuse.com/#feat=svg
-	 */
-	public function force_svg_support() {
-		$this->dom->documentElement->setAttribute(
-			'class',
-			preg_replace(
-				'/(^|\s)no-svg(\s|$)/',
-				' svg ',
-				$this->dom->documentElement->getAttribute( 'class' )
-			)
-		);
-	}
-
-	/**
-	 * Force support for fixed background-attachment.
-	 *
-	 * @since 1.0
-	 *
-	 * @link https://github.com/WordPress/wordpress-develop/blob/1af1f65a21a1a697fb5f33027497f9e5ae638453/src/wp-content/themes/twentyseventeen/assets/js/global.js#L215-L217
-	 * @link https://caniuse.com/#feat=background-attachment
-	 */
-	public function force_fixed_background_support() {
-		$this->dom->documentElement->setAttribute(
-			'class',
-			$this->dom->documentElement->getAttribute( 'class' ) . ' background-fixed'
-		);
-	}
-
-	/**
-	 * Add body class when there is a header video.
-	 *
-	 * @since 1.0
-	 * @link https://github.com/WordPress/wordpress-develop/blob/a26c24226c6b131a0ed22c722a836c100d3ba254/src/wp-content/themes/twentyseventeen/assets/js/global.js#L244-L247
-	 *
-	 * @param array $args Args.
-	 */
-	public static function add_has_header_video_body_class( $args = array() ) {
-		$args = array_merge(
-			array(
-				'class_name' => 'has-header-video',
-			),
-			$args
-		);
-
-		add_filter( 'body_class', function( $body_classes ) use ( $args ) {
-			if ( has_header_video() ) {
-				$body_classes[] = $args['class_name'];
-			}
-			return $body_classes;
-		} );
-	}
-
-	/**
-	 * Get the (common) navigation outer height.
-	 *
-	 * @todo If the nav menu has many items and it spans multiple rows, this will be too small.
-	 * @link https://github.com/WordPress/wordpress-develop/blob/fd5ba80c5c3d9cf62348567073945e246285fbca/src/wp-content/themes/twentyseventeen/assets/js/global.js#L50
-	 *
-	 * @return int Navigation outer height.
-	 */
-	protected static function get_twentyseventeen_navigation_outer_height() {
-		return 72;
-	}
-
-	/**
-	 * Add required styles for featured image header in Twenty Nineteen.
-	 *
-	 * The following is necessary because the styles in the theme apply to the featured img,
-	 * and the CSS parser will then convert the selectors to amp-img. Nevertheless, object-fit
-	 * does not apply on amp-img and it needs to apply on an actual img.
-	 *
-	 * @link https://github.com/WordPress/wordpress-develop/blob/5.0/src/wp-content/themes/twentynineteen/style.css#L2276-L2299
-	 * @since 1.0
-	 */
-	public static function add_twentynineteen_masthead_styles() {
-		add_action( 'wp_enqueue_scripts', function() {
-			ob_start();
-			?>
-			<style>
-			.site-header.featured-image .site-featured-image .post-thumbnail amp-img > img {
-				height: auto;
-				left: 50%;
-				max-width: 1000%;
-				min-height: 100%;
-				min-width: 100vw;
-				position: absolute;
-				top: 50%;
-				transform: translateX(-50%) translateY(-50%);
-				width: auto;
-				z-index: 1;
-				/* When image filters are active, make it grayscale to colorize it blue. */
-			}
-
-			@supports (object-fit: cover) {
-				.site-header.featured-image .site-featured-image .post-thumbnail amp-img > img {
-					height: 100%;
-					left: 0;
-					object-fit: cover;
-					top: 0;
-					transform: none;
-					width: 100%;
-				}
-			}
-			</style>
-			<?php
-			$styles = str_replace( array( '<style>', '</style>' ), '', ob_get_clean() );
-			wp_add_inline_style( get_template() . '-style', $styles );
-		}, 11 );
-	}
-
-	/**
-	 * Add required styles for video and image headers.
-	 *
-	 * This is currently used exclusively for Twenty Seventeen.
-	 *
-	 * @since 1.0
-	 * @link https://github.com/WordPress/wordpress-develop/blob/1af1f65a21a1a697fb5f33027497f9e5ae638453/src/wp-content/themes/twentyseventeen/style.css#L1687
-	 * @link https://github.com/WordPress/wordpress-develop/blob/1af1f65a21a1a697fb5f33027497f9e5ae638453/src/wp-content/themes/twentyseventeen/style.css#L1743
-	 */
-	public static function add_twentyseventeen_masthead_styles() {
-		$args = self::get_theme_config( get_template() );
-
-		/*
-		 * The following is necessary because the styles in the theme apply to img and video,
-		 * and the CSS parser will then convert the selectors to amp-img and amp-video respectively.
-		 * Nevertheless, object-fit does not apply on amp-img and it needs to apply on an actual img.
-		 */
-		add_action( 'wp_enqueue_scripts', function() use ( $args ) {
-			$is_front_page_layout = ( is_front_page() && 'posts' !== get_option( 'show_on_front' ) ) || ( is_home() && is_front_page() );
-			ob_start();
-			?>
-			<style>
-				.has-header-image .custom-header-media amp-img > img,
-				.has-header-video .custom-header-media amp-video > video{
-					position: fixed;
-					height: auto;
-					left: 50%;
-					max-width: 1000%;
-					min-height: 100%;
-					min-width: 100%;
-					min-width: 100vw; /* vw prevents 1px gap on left that 100% has */
-					width: auto;
-					top: 50%;
-					padding-bottom: 1px; /* Prevent header from extending beyond the footer */
-					-ms-transform: translateX(-50%) translateY(-50%);
-					-moz-transform: translateX(-50%) translateY(-50%);
-					-webkit-transform: translateX(-50%) translateY(-50%);
-					transform: translateX(-50%) translateY(-50%);
-				}
-				.has-header-image:not(.twentyseventeen-front-page):not(.home) .custom-header-media amp-img > img {
-					bottom: 0;
-					position: absolute;
-					top: auto;
-					-ms-transform: translateX(-50%) translateY(0);
-					-moz-transform: translateX(-50%) translateY(0);
-					-webkit-transform: translateX(-50%) translateY(0);
-					transform: translateX(-50%) translateY(0);
-				}
-				/* For browsers that support object-fit */
-				@supports ( object-fit: cover ) {
-					.has-header-image .custom-header-media amp-img > img,
-					.has-header-video .custom-header-media amp-video > video,
-					.has-header-image:not(.twentyseventeen-front-page):not(.home) .custom-header-media amp-img > img {
-						height: 100%;
-						left: 0;
-						-o-object-fit: cover;
-						object-fit: cover;
-						top: 0;
-						-ms-transform: none;
-						-moz-transform: none;
-						-webkit-transform: none;
-						transform: none;
-						width: 100%;
-					}
-				}
-
-				.navigation-top.site-navigation-fixed {
-					display: none;
-				}
-
-				<?php if ( $is_front_page_layout && ! has_custom_header() ) : ?>
-					/* https://github.com/WordPress/wordpress-develop/blob/fd5ba80c5c3d9cf62348567073945e246285fbca/src/wp-content/themes/twentyseventeen/assets/js/global.js#L92-L94 */
-					.site-branding {
-						margin-bottom: <?php echo (int) AMP_Core_Theme_Sanitizer::get_twentyseventeen_navigation_outer_height(); ?>px;
-					}
-				<?php endif; ?>
-
-				@media screen and (min-width: 48em) {
-					/* Note that adjustHeaderHeight() is irrelevant with this change */
-					<?php if ( ! $is_front_page_layout ) : ?>
-						.navigation-top {
-							position: static;
-						}
-					<?php endif; ?>
-
-					/* Initial styles that amp-animations for navigationTopShow and navigationTopHide will override */
-					.navigation-top.site-navigation-fixed {
-						opacity: 0;
-						transform: translateY( -<?php echo (int) AMP_Core_Theme_Sanitizer::get_twentyseventeen_navigation_outer_height(); ?>px );
-						display: block;
-					}
-				}
-			</style>
-			<?php
-			$styles = str_replace( array( '<style>', '</style>' ), '', ob_get_clean() );
-			wp_add_inline_style( get_template() . '-style', $styles );
-		}, 11 );
-	}
-
-	/**
-	 * Add sticky nav menu to Twenty Seventeen.
-	 *
-	 * This is implemented by cloning the navigation-top element, giving it a fixed position outside of the viewport,
-	 * and then showing it at the top of the window as soon as the original nav begins to get scrolled out of view.
-	 * In order to improve accessibility, the cloned nav gets aria-hidden=true and all of the links get tabindex=-1
-	 * to prevent the keyboard from focusing on elements off the screen; it is not necessary to focus on the elements
-	 * in the fixed nav menu because as soon as the original nav menu is focused then the window is scrolled to the
-	 * top anyway.
-	 *
-	 * @since 1.0
-	 */
-	public function add_twentyseventeen_sticky_nav_menu() {
-		/**
-		 * Elements.
-		 *
-		 * @var DOMElement $link
-		 * @var DOMElement $navigation_top
-		 * @var DOMElement $navigation_top_fixed
-		 */
-		$navigation_top = $this->xpath->query( '//header[ @id = "masthead" ]//div[ contains( @class, "navigation-top" ) ]' )->item( 0 );
-		if ( ! $navigation_top ) {
-			return;
-		}
-
-		$navigation_top_fixed = $navigation_top->cloneNode( true );
-		$navigation_top_fixed->setAttribute( 'class', $navigation_top_fixed->getAttribute( 'class' ) . ' site-navigation-fixed' );
-
-		$navigation_top_fixed->setAttribute( 'aria-hidden', 'true' );
-		foreach ( $navigation_top_fixed->getElementsByTagName( 'a' ) as $link ) {
-			$link->setAttribute( 'tabindex', '-1' );
-		}
-
-		$navigation_top->parentNode->insertBefore( $navigation_top_fixed, $navigation_top->nextSibling );
-
-		$attributes = array(
-			'layout'              => 'nodisplay',
-			'intersection-ratios' => 1,
-			'on'                  => implode( ';', array(
-				'exit:navigationTopShow.start',
-				'enter:navigationTopHide.start',
-			) ),
-		);
-		if ( is_admin_bar_showing() ) {
-			$attributes['viewport-margins'] = '32px 0';
-		}
-		$position_observer = AMP_DOM_Utils::create_node( $this->dom, 'amp-position-observer', $attributes );
-		$navigation_top->appendChild( $position_observer );
-
-		$animations = array(
-			'navigationTopShow' => array(
-				'duration'   => 0,
-				'fill'       => 'both',
-				'animations' => array(
-					'selector'  => '.navigation-top.site-navigation-fixed',
-					'media'     => '(min-width: 48em)',
-					'keyframes' => array(
-						'opacity'   => 1.0,
-						'transform' => 'translateY( 0 )',
-					),
-				),
-			),
-			'navigationTopHide' => array(
-				'duration'   => 0,
-				'fill'       => 'both',
-				'animations' => array(
-					'selector'  => '.navigation-top.site-navigation-fixed',
-					'media'     => '(min-width: 48em)',
-					'keyframes' => array(
-						'opacity'   => 0.0,
-						'transform' => sprintf( 'translateY( -%dpx )', self::get_twentyseventeen_navigation_outer_height() ),
-					),
-				),
-			),
-		);
-
-		foreach ( $animations as $animation_id => $animation ) {
-			$amp_animation   = AMP_DOM_Utils::create_node( $this->dom, 'amp-animation', array(
-				'id'     => $animation_id,
-				'layout' => 'nodisplay',
-			) );
-			$position_script = $this->dom->createElement( 'script' );
-			$position_script->setAttribute( 'type', 'application/json' );
-			$position_script->appendChild( $this->dom->createTextNode( wp_json_encode( $animation ) ) );
-			$amp_animation->appendChild( $position_script );
-			$this->body->appendChild( $amp_animation );
-		}
-	}
-
-	/**
-	 * Add styles for the nav menu specifically to deal with AMP running in a no-js context.
-	 *
-	 * @since 1.0
-	 *
-	 * @param array $args Args.
-	 */
-	public static function add_nav_menu_styles( $args = array() ) {
-		$args = array_merge(
-			self::get_theme_config( get_template() ),
-			$args
-		);
-
-		add_action( 'wp_enqueue_scripts', function() use ( $args ) {
-			ob_start();
-			?>
-			<style>
-				/* Override no-js selector in parent theme. */
-				.no-js .main-navigation ul ul {
-					display: none;
-				}
-
-				/* Use sibling selector and re-use class on button instead of toggling toggle-on class on ul.sub-menu */
-				.main-navigation ul .<?php echo esc_html( $args['sub_menu_button_toggle_class'] ); ?> + .sub-menu {
-					display: block;
-				}
-
-				<?php if ( 'twentyseventeen' === get_template() ) : ?>
-					/* Show the button*/
-					.no-js .<?php echo esc_html( $args['menu_button_class'] ); ?> {
-						display: block;
-					}
-					.no-js .main-navigation > div > ul {
-						display: none;
-					}
-					.no-js .main-navigation.<?php echo esc_html( $args['nav_container_toggle_class'] ); ?> > div > ul {
-						display: block;
-					}
-					@media screen and (min-width: 48em) {
-						.no-js .<?php echo esc_html( $args['menu_button_class'] ); ?>,
-						.no-js .<?php echo esc_html( $args['sub_menu_button_class'] ); ?> {
-							display: none;
-						}
-						.no-js .main-navigation ul,
-						.no-js .main-navigation ul ul,
-						.no-js .main-navigation > div > ul {
-							display: block;
-						}
-						.main-navigation ul li.menu-item-has-children:focus-within:before,
-						.main-navigation ul li.menu-item-has-children:focus-within:after,
-						.main-navigation ul li.page_item_has_children:focus-within:before,
-						.main-navigation ul li.page_item_has_children:focus-within:after {
-							display: block;
-						}
-						.main-navigation ul ul li:focus-within > ul {
-							<?php if ( is_rtl() ) : ?>
-								left: auto;
-								right: 100%;
-							<?php else : ?>
-								left: 100%;
-								right: auto;
-							<?php endif; ?>
-						}
-						.main-navigation li li:focus-within {
-							background: #767676;
-						}
-						.main-navigation li li:focus-within > a,
-						.main-navigation li li a:focus-within,
-						.main-navigation li li.current_page_item a:focus-within,
-						.main-navigation li li.current-menu-item a:focus-within {
-							color: #fff;
-						}
-						.main-navigation ul li:focus-within > ul {
-							<?php if ( is_rtl() ) : ?>
-								left: auto;
-								right: 0.5em;
-							<?php else : ?>
-								left: 0.5em;
-								right: auto;
-							<?php endif; ?>
-						}
-
-						.main-navigation ul ul li.menu-item-has-children:focus-within:before,
-						.main-navigation ul ul li.menu-item-has-children:focus-within:after,
-						.main-navigation ul ul li.page_item_has_children:focus-within:before,
-						.main-navigation ul ul li.page_item_has_children:focus-within:after {
-							display: none;
-						}
-					}
-				<?php elseif ( 'twentysixteen' === get_template() ) : ?>
-					@media screen and (max-width: 56.875em) {
-						/* Show the button*/
-						.no-js .<?php echo esc_html( $args['menu_button_class'] ); ?> {
-							display: block;
-						}
-						.no-js .site-header-menu {
-							display: none;
-						}
-						.no-js .site-header-menu.toggled-on {
-							display: block;
-						}
-					}
-					@media screen and (min-width: 56.875em) {
-						.no-js .main-navigation ul ul {
-							display: block;
-						}
-						.main-navigation li:focus-within > a {
-							color: #007acc;
-						}
-						.main-navigation li:focus-within > ul {
-							<?php if ( is_rtl() ) : ?>
-								left: auto;
-								right: 0;
-							<?php else : ?>
-								left: 0;
-								right: auto;
-							<?php endif; ?>
-						}
-						.main-navigation ul ul li:focus-within > ul {
-							<?php if ( is_rtl() ) : ?>
-								left: 100%;
-								right: auto;
-							<?php else : ?>
-								left: auto;
-								right: 100%;
-							<?php endif; ?>
-						}
-					}
-				<?php elseif ( 'twentyfifteen' === get_template() ) : ?>
-					@media screen and (min-width: 59.6875em) {
-						/* Attempt to emulate https://github.com/WordPress/wordpress-develop/blob/5e9a39baa7d4368f7d3c36dcbcd53db6317677c9/src/wp-content/themes/twentyfifteen/js/functions.js#L108-L149 */
-						#sidebar {
-							position: sticky;
-							top: -9vh;
-							max-height: 109vh;
-							overflow-y: auto;
-						}
-					}
-
-				<?php endif; ?>
-			</style>
-			<?php
-			$styles = str_replace( array( '<style>', '</style>' ), '', ob_get_clean() );
-			wp_add_inline_style( get_template() . '-style', $styles );
-		}, 11 );
-	}
-
-	/**
-	 * Ensure that JS-only nav menu styles apply to AMP as well since even though scripts are not allowed, there are AMP-bind implementations.
-	 *
-	 * @since 1.0
-	 *
-	 * @param array $args Args.
-	 */
-	public function add_nav_menu_toggle( $args = array() ) {
-		$args = array_merge(
-			self::get_theme_config( get_template() ),
-			$args
-		);
-
-		$nav_el    = $this->dom->getElementById( $args['nav_container_id'] );
-		$button_el = $this->xpath->query( $args['menu_button_xpath'] )->item( 0 );
-		if ( ! $nav_el ) {
-			if ( $button_el ) {
-
-				// Remove the button since it won't be used.
-				$button_el->parentNode->removeChild( $button_el );
-			}
-			return;
-		}
-
-		if ( ! $button_el ) {
-			return;
-		}
-
-		$state_id = 'navMenuToggledOn';
-		$expanded = false;
-
-		$nav_el->setAttribute(
-			AMP_DOM_Utils::get_amp_bind_placeholder_prefix() . 'class',
-			sprintf(
-				"%s + ( $state_id ? %s : '' )",
-				wp_json_encode( $nav_el->getAttribute( 'class' ) ),
-				wp_json_encode( ' ' . $args['nav_container_toggle_class'] )
-			)
-		);
-
-		$state_el = $this->dom->createElement( 'amp-state' );
-		$state_el->setAttribute( 'id', $state_id );
-		$script_el = $this->dom->createElement( 'script' );
-		$script_el->setAttribute( 'type', 'application/json' );
-		$script_el->appendChild( $this->dom->createTextNode( wp_json_encode( $expanded ) ) );
-		$state_el->appendChild( $script_el );
-		$nav_el->parentNode->insertBefore( $state_el, $nav_el );
-
-		$button_on = sprintf( "tap:AMP.setState({ $state_id: ! $state_id })" );
-		$button_el->setAttribute( 'on', $button_on );
-		$button_el->setAttribute( 'aria-expanded', 'false' );
-		$button_el->setAttribute( AMP_DOM_Utils::get_amp_bind_placeholder_prefix() . 'aria-expanded', "$state_id ? 'true' : 'false'" );
-		$button_el->setAttribute(
-			AMP_DOM_Utils::get_amp_bind_placeholder_prefix() . 'class',
-			sprintf( "%s + ( $state_id ? %s : '' )", wp_json_encode( $button_el->getAttribute( 'class' ) ), wp_json_encode( ' ' . $args['menu_button_toggle_class'] ) )
-		);
-	}
-
-	/**
-	 * Add buttons for nav sub-menu items.
-	 *
-	 * @since 1.0
-	 * @link https://github.com/WordPress/wordpress-develop/blob/a26c24226c6b131a0ed22c722a836c100d3ba254/src/wp-content/themes/twentyseventeen/assets/js/navigation.js#L11-L43
-	 *
-	 * @param array $args Args.
-	 */
-	public static function add_nav_sub_menu_buttons( $args = array() ) {
-		$default_args = self::get_theme_config( get_template() );
-		switch ( get_template() ) {
-			case 'twentyseventeen':
-				if ( function_exists( 'twentyseventeen_get_svg' ) ) {
-					$default_args['icon'] = twentyseventeen_get_svg( array(
-						'icon'     => 'angle-down',
-						'fallback' => true,
-					) );
-				}
-				break;
-		}
-		$args = array_merge( $default_args, $args );
-
-		/**
-		 * Filter the HTML output of a nav menu item to add the AMP dropdown button to reveal the sub-menu.
-		 *
-		 * @see twentyfifteen_amp_setup_hooks()
-		 *
-		 * @param string $item_output Nav menu item HTML.
-		 * @param object $item        Nav menu item.
-		 * @return string Modified nav menu item HTML.
-		 */
-		add_filter( 'walker_nav_menu_start_el', function( $item_output, $item, $depth, $nav_menu_args ) use ( $args ) {
-			unset( $depth );
-
-			// Skip adding buttons to nav menu widgets for now.
-			if ( empty( $nav_menu_args->theme_location ) ) {
-				return $item_output;
-			}
-
-			if ( ! in_array( 'menu-item-has-children', $item->classes, true ) ) {
-				return $item_output;
-			}
-			static $nav_menu_item_number = 0;
-			$nav_menu_item_number++;
-
-			$expanded = in_array( 'current-menu-ancestor', $item->classes, true );
-
-			$expanded_state_id = 'navMenuItemExpanded' . $nav_menu_item_number;
-
-			// Create new state for managing storing the whether the sub-menu is expanded.
-			$item_output .= sprintf(
-				'<amp-state id="%s"><script type="application/json">%s</script></amp-state>',
-				esc_attr( $expanded_state_id ),
-				wp_json_encode( $expanded )
-			);
-
-			$dropdown_button  = '<button';
-			$dropdown_button .= sprintf(
-				' class="%s" [class]="%s"',
-				esc_attr( $args['sub_menu_button_class'] . ( $expanded ? ' ' . $args['sub_menu_button_toggle_class'] : '' ) ),
-				esc_attr( sprintf( "%s + ( $expanded_state_id ? %s : '' )", wp_json_encode( $args['sub_menu_button_class'] ), wp_json_encode( ' ' . $args['sub_menu_button_toggle_class'] ) ) )
-			);
-			$dropdown_button .= sprintf(
-				' aria-expanded="%s" [aria-expanded]="%s"',
-				esc_attr( wp_json_encode( $expanded ) ),
-				esc_attr( "$expanded_state_id ? 'true' : 'false'" )
-			);
-			$dropdown_button .= sprintf(
-				' on="%s"',
-				esc_attr( "tap:AMP.setState( { $expanded_state_id: ! $expanded_state_id } )" )
-			);
-			$dropdown_button .= '>';
-
-			if ( isset( $args['icon'] ) ) {
-				$dropdown_button .= $args['icon'];
-			}
-			if ( isset( $args['expand_text'] ) && isset( $args['collapse_text'] ) ) {
-				$dropdown_button .= sprintf(
-					'<span class="screen-reader-text" [text]="%s">%s</span>',
-					esc_attr( sprintf( "$expanded_state_id ? %s : %s", wp_json_encode( $args['collapse_text'] ), wp_json_encode( $args['expand_text'] ) ) ),
-					esc_html( $expanded ? $args['collapse_text'] : $args['expand_text'] )
-				);
-			}
-
-			$dropdown_button .= '</button>';
-
-			$item_output .= $dropdown_button;
-			return $item_output;
-		}, 10, 4 );
-	}
-
-	/**
-	 * Output image styles for twentynineteen.
-	 *
-	 * When <img> tags have an 'aligncenter' class, AMP_Img_Sanitizer::handle_centering() wraps theme in <figure class="aligncenter">.
-	 * This ensures that the image inside it is centered.
-	 *
-	 * @since 1.0
-	 *
-	 * @param array $args Arguments.
-	 */
-	public static function add_twentynineteen_image_styles( $args = array() ) {
-		add_action( 'wp_enqueue_scripts', function() use ( $args ) {
-			ob_start();
-			?>
-			<style>
-				figure.aligncenter {
-					text-align: center
-				}
-			</style>
-			<?php
-			$styles = str_replace( array( '<style>', '</style>' ), '', ob_get_clean() );
-			wp_add_inline_style( get_template() . '-style', $styles );
-		}, 11 );
-	}
-}
diff --git a/includes/sanitizers/class-amp-embed-sanitizer.php b/includes/sanitizers/class-amp-embed-sanitizer.php
deleted file mode 100644
index 6d32afd5b18..00000000000
--- a/includes/sanitizers/class-amp-embed-sanitizer.php
+++ /dev/null
@@ -1,47 +0,0 @@
-<?php
-/**
- * Class AMP_Embed_Sanitizer
- *
- * @package AMP
- */
-
-/**
- * Class AMP_Embed_Sanitizer
- *
- * Calls sanitize_raw_embeds method on embed handlers.
- */
-class AMP_Embed_Sanitizer extends AMP_Base_Sanitizer {
-
-	/**
-	 * Embed handlers.
-	 *
-	 * @var AMP_Base_Embed_Handler[] AMP_Base_Embed_Handler[]
-	 */
-	private $embed_handlers = array();
-
-	/**
-	 * AMP_Embed_Sanitizer constructor.
-	 *
-	 * @param DOMDocument $dom  DOM.
-	 * @param array       $args Args.
-	 */
-	public function __construct( $dom, $args = array() ) {
-		parent::__construct( $dom, $args );
-
-		if ( ! empty( $this->args['embed_handlers'] ) ) {
-			$this->embed_handlers = $this->args['embed_handlers'];
-		}
-	}
-
-	/**
-	 * Checks if each embed_handler has sanitize_raw_method and calls it.
-	 */
-	public function sanitize() {
-
-		foreach ( $this->embed_handlers as $embed_handler ) {
-			if ( method_exists( $embed_handler, 'sanitize_raw_embeds' ) ) {
-				$embed_handler->sanitize_raw_embeds( $this->dom );
-			}
-		}
-	}
-}
diff --git a/includes/sanitizers/class-amp-form-sanitizer.php b/includes/sanitizers/class-amp-form-sanitizer.php
deleted file mode 100644
index 03babed13c5..00000000000
--- a/includes/sanitizers/class-amp-form-sanitizer.php
+++ /dev/null
@@ -1,156 +0,0 @@
-<?php
-/**
- * Class AMP_Form_Sanitizer.
- *
- * @package AMP
- * @since 0.7
- */
-
-/**
- * Class AMP_Form_Sanitizer
- *
- * Strips and corrects attributes in forms.
- *
- * @since 0.7
- */
-class AMP_Form_Sanitizer extends AMP_Base_Sanitizer {
-
-	/**
-	 * Tag.
-	 *
-	 * @var string HTML <form> tag to identify and process.
-	 *
-	 * @since 0.7
-	 */
-	public static $tag = 'form';
-
-	/**
-	 * Get mapping of HTML selectors to the AMP component selectors which they may be converted into.
-	 *
-	 * @return array Mapping.
-	 */
-	public function get_selector_conversion_mapping() {
-		return array(
-			'form' => array( 'amp-form' ),
-		);
-	}
-
-	/**
-	 * Sanitize the <form> elements from the HTML contained in this instance's DOMDocument.
-	 *
-	 * @link https://www.ampproject.org/docs/reference/components/amp-form
-	 * @since 0.7
-	 */
-	public function sanitize() {
-
-		/**
-		 * Node list.
-		 *
-		 * @var DOMNodeList $node
-		 */
-		$nodes     = $this->dom->getElementsByTagName( self::$tag );
-		$num_nodes = $nodes->length;
-
-		if ( 0 === $num_nodes ) {
-			return;
-		}
-
-		for ( $i = $num_nodes - 1; $i >= 0; $i-- ) {
-			$node = $nodes->item( $i );
-			if ( ! $node instanceof DOMElement ) {
-				continue;
-			}
-
-			// In HTML, the default method is 'get'.
-			$method = 'get';
-			if ( $node->getAttribute( 'method' ) ) {
-				$method = strtolower( $node->getAttribute( 'method' ) );
-			} else {
-				$node->setAttribute( 'method', $method );
-			}
-
-			/*
-			 * In HTML, the default action is just the current URL that the page is served from.
-			 * The action "specifies a server endpoint to handle the form input. The value must be an
-			 * https URL and must not be a link to a CDN".
-			 */
-			if ( ! $node->getAttribute( 'action' ) ) {
-				$action_url = esc_url_raw( '//' . $_SERVER['HTTP_HOST'] . wp_unslash( $_SERVER['REQUEST_URI'] ) ); // WPCS: ignore. input var okay, sanitization ok.
-			} else {
-				$action_url = $node->getAttribute( 'action' );
-				// Check if action_url is a relative path and add the host to it.
-				if ( ! preg_match( '#^(https?:)?//#', $action_url ) ) {
-					$action_url = esc_url_raw( '//' . $_SERVER['HTTP_HOST'] . $action_url );
-				}
-			}
-			$xhr_action = $node->getAttribute( 'action-xhr' );
-
-			// Make HTTP URLs protocol-less, since HTTPS is required for forms.
-			if ( 'http://' === strtolower( substr( $action_url, 0, 7 ) ) ) {
-				$action_url = substr( $action_url, 5 );
-			}
-
-			/*
-			 * "For GET submissions, provide at least one of action or action-xhr".
-			 * "This attribute is required for method=GET. For method=POST, the
-			 * action attribute is invalid, use action-xhr instead".
-			 */
-			if ( 'get' === $method ) {
-				if ( $action_url !== $node->getAttribute( 'action' ) ) {
-					$node->setAttribute( 'action', $action_url );
-				}
-			} elseif ( 'post' === $method ) {
-				$node->removeAttribute( 'action' );
-				if ( ! $xhr_action ) {
-					// record that action was converted tp action-xhr.
-					$action_url = add_query_arg( '_wp_amp_action_xhr_converted', 1, $action_url );
-					$node->setAttribute( 'action-xhr', $action_url );
-					// Append error handler if not found.
-					$this->ensure_submit_error_element( $node );
-				} elseif ( 'http://' === substr( $xhr_action, 0, 7 ) ) {
-					$node->setAttribute( 'action-xhr', substr( $xhr_action, 5 ) );
-				}
-			}
-
-			/*
-			 * The target "indicates where to display the form response after submitting the form.
-			 * The value must be _blank or _top". The _self and _parent values are treated
-			 * as synonymous with _top, and anything else is treated like _blank.
-			 */
-			$target = $node->getAttribute( 'target' );
-			if ( '_top' !== $target ) {
-				if ( ! $target || in_array( $target, array( '_self', '_parent' ), true ) ) {
-					$node->setAttribute( 'target', '_top' );
-				} elseif ( '_blank' !== $target ) {
-					$node->setAttribute( 'target', '_blank' );
-				}
-			}
-		}
-	}
-
-	/**
-	 * Checks if the form has an error handler else create one if not.
-	 *
-	 * @link https://www.ampproject.org/docs/reference/components/amp-form#success/error-response-rendering
-	 * @since 0.7
-	 *
-	 * @param DOMElement $form The form node to check.
-	 */
-	public function ensure_submit_error_element( $form ) {
-		$templates = $form->getElementsByTagName( 'template' );
-		for ( $i = $templates->length - 1; $i >= 0; $i-- ) {
-			if ( $templates->item( $i )->parentNode->hasAttribute( 'submit-error' ) ) {
-				return; // Found error template, do nothing.
-			}
-		}
-
-		$div      = $this->dom->createElement( 'div' );
-		$template = $this->dom->createElement( 'template' );
-		$mustache = $this->dom->createTextNode( '{{{error}}}' );
-		$div->setAttribute( 'submit-error', '' );
-		$template->setAttribute( 'type', 'amp-mustache' );
-		$template->appendChild( $mustache );
-		$div->appendChild( $template );
-		$form->appendChild( $div );
-	}
-}
diff --git a/includes/sanitizers/class-amp-gallery-block-sanitizer.php b/includes/sanitizers/class-amp-gallery-block-sanitizer.php
deleted file mode 100644
index beda1cfb0c3..00000000000
--- a/includes/sanitizers/class-amp-gallery-block-sanitizer.php
+++ /dev/null
@@ -1,207 +0,0 @@
-<?php
-/**
- * Class AMP_Gallery_Block_Sanitizer.
- *
- * @package AMP
- */
-
-/**
- * Class AMP_Gallery_Block_Sanitizer
- *
- * Modifies gallery block to match the block's AMP-specific configuration.
- */
-class AMP_Gallery_Block_Sanitizer extends AMP_Base_Sanitizer {
-
-	/**
-	 * Value used for width of amp-carousel.
-	 *
-	 * @since 1.0
-	 *
-	 * @const int
-	 */
-	const FALLBACK_WIDTH = 600;
-
-	/**
-	 * Value used for height of amp-carousel.
-	 *
-	 * @since 1.0
-	 *
-	 * @const int
-	 */
-	const FALLBACK_HEIGHT = 480;
-
-	/**
-	 * Tag.
-	 *
-	 * @since 1.0
-	 *
-	 * @var string Ul tag to identify wrapper around gallery block.
-	 */
-	public static $tag = 'ul';
-
-	/**
-	 * Expected class of the wrapper around the gallery block.
-	 *
-	 * @since 1.0
-	 *
-	 * @var string
-	 */
-	public static $class = 'wp-block-gallery';
-
-	/**
-	 * Array of flags used to control sanitization.
-	 *
-	 * @var array {
-	 *      @type int  $content_max_width Max width of content.
-	 *      @type bool $carousel_required Whether carousels are required. This is used when amp theme support is not present, for back-compat.
-	 * }
-	 */
-	protected $args;
-
-	/**
-	 * Default args.
-	 *
-	 * @var array
-	 */
-	protected $DEFAULT_ARGS = array(
-		'carousel_required' => false,
-	);
-
-	/**
-	 * Sanitize the gallery block contained by <ul> element where necessary.
-	 *
-	 * @since 0.2
-	 */
-	public function sanitize() {
-		$nodes     = $this->dom->getElementsByTagName( self::$tag );
-		$num_nodes = $nodes->length;
-		if ( 0 === $num_nodes ) {
-			return;
-		}
-
-		for ( $i = $num_nodes - 1; $i >= 0; $i-- ) {
-			$node = $nodes->item( $i );
-
-			// We're looking for <ul> elements that have at least one child and the proper class.
-			if ( 0 === count( $node->childNodes ) || false === strpos( $node->getAttribute( 'class' ), self::$class ) ) {
-				continue;
-			}
-
-			$attributes      = AMP_DOM_Utils::get_node_attributes_as_assoc_array( $node );
-			$is_amp_lightbox = isset( $attributes['data-amp-lightbox'] ) && true === filter_var( $attributes['data-amp-lightbox'], FILTER_VALIDATE_BOOLEAN );
-			$is_amp_carousel = ! empty( $this->args['carousel_required'] ) || ( isset( $attributes['data-amp-carousel'] ) && true === filter_var( $attributes['data-amp-carousel'], FILTER_VALIDATE_BOOLEAN ) );
-
-			// We are only looking for <ul> elements which have amp-carousel / amp-lightbox true.
-			if ( ! $is_amp_carousel && ! $is_amp_lightbox ) {
-				continue;
-			}
-
-			// If lightbox is set, we should add lightbox feature to the gallery images.
-			if ( $is_amp_lightbox ) {
-				$this->add_lightbox_attributes_to_image_nodes( $node );
-				$this->maybe_add_amp_image_lightbox_node();
-			}
-
-			// If amp-carousel is not set, nothing else to do here.
-			if ( ! $is_amp_carousel ) {
-				continue;
-			}
-
-			$images = array();
-
-			// If it's not AMP lightbox, look for links first.
-			if ( ! $is_amp_lightbox ) {
-				foreach ( $node->getElementsByTagName( 'a' ) as $element ) {
-					$images[] = $element;
-				}
-			}
-
-			// If not linking to anything then look for <amp-img>.
-			if ( empty( $images ) ) {
-				foreach ( $node->getElementsByTagName( 'amp-img' ) as $element ) {
-					$images[] = $element;
-				}
-			}
-
-			// Skip if no images found.
-			if ( empty( $images ) ) {
-				continue;
-			}
-
-			$amp_carousel = AMP_DOM_Utils::create_node( $this->dom, 'amp-carousel', array(
-				'height' => $this->get_carousel_height( $node ),
-				'type'   => 'slides',
-				'layout' => 'fixed-height',
-			) );
-			foreach ( $images as $image ) {
-				$amp_carousel->appendChild( $image );
-			}
-
-			$node->parentNode->replaceChild( $amp_carousel, $node );
-		}
-		$this->did_convert_elements = true;
-	}
-
-	/**
-	 * Get carousel height by containing images.
-	 *
-	 * @param DOMElement $element The UL element.
-	 * @return int Height.
-	 */
-	protected function get_carousel_height( $element ) {
-		$images     = $element->getElementsByTagName( 'amp-img' );
-		$num_images = $images->length;
-		$max_height = 0;
-		$max_width  = 0;
-		if ( 0 === $num_images ) {
-			return self::FALLBACK_HEIGHT;
-		}
-		foreach ( $images as $image ) {
-			/**
-			 * Image.
-			 *
-			 * @var DOMElement $image
-			 */
-			$image_height = $image->getAttribute( 'height' );
-			if ( is_numeric( $image_height ) ) {
-				$max_height = max( $max_height, $image_height );
-			}
-			$image_width = $image->getAttribute( 'height' );
-			if ( is_numeric( $image_width ) ) {
-				$max_width = max( $max_width, $image_width );
-			}
-		}
-
-		if ( ! empty( $this->args['content_max_width'] ) && $max_height > 0 && $max_width > $this->args['content_max_width'] ) {
-			$max_height = ( $max_width * $this->args['content_max_width'] ) / $max_height;
-		}
-
-		return ! $max_height ? self::FALLBACK_HEIGHT : $max_height;
-	}
-
-	/**
-	 * Set lightbox related attributes to <amp-img> within gallery.
-	 *
-	 * @param DOMElement $element The UL element.
-	 */
-	protected function add_lightbox_attributes_to_image_nodes( $element ) {
-		$images     = $element->getElementsByTagName( 'amp-img' );
-		$num_images = $images->length;
-		if ( 0 === $num_images ) {
-			return;
-		}
-		$attributes = array(
-			'data-amp-lightbox' => '',
-			'on'                => 'tap:' . self::AMP_IMAGE_LIGHTBOX_ID,
-			'role'              => 'button',
-			'tabindex'          => 0,
-		);
-
-		for ( $j = $num_images - 1; $j >= 0; $j-- ) {
-			$image_node = $images->item( $j );
-			foreach ( $attributes as $att => $value ) {
-				$image_node->setAttribute( $att, $value );
-			}
-		}
-	}
-}
diff --git a/includes/sanitizers/class-amp-iframe-sanitizer.php b/includes/sanitizers/class-amp-iframe-sanitizer.php
deleted file mode 100644
index 267992104bd..00000000000
--- a/includes/sanitizers/class-amp-iframe-sanitizer.php
+++ /dev/null
@@ -1,196 +0,0 @@
-<?php
-/**
- * Class AMP_Iframe_Sanitizer
- *
- * @package AMP
- */
-
-/**
- * Class AMP_Iframe_Sanitizer
- *
- * Converts <iframe> tags to <amp-iframe>
- */
-class AMP_Iframe_Sanitizer extends AMP_Base_Sanitizer {
-
-	/**
-	 * Value used for height attribute when $attributes['height'] is empty.
-	 *
-	 * @since 0.2
-	 *
-	 * @const int
-	 */
-	const FALLBACK_HEIGHT = 400;
-
-	/**
-	 * Default values for sandboxing IFrame.
-	 *
-	 * @since 0.2
-	 *
-	 * @const int
-	 */
-	const SANDBOX_DEFAULTS = 'allow-scripts allow-same-origin';
-
-	/**
-	 * Tag.
-	 *
-	 * @var string HTML <iframe> tag to identify and replace with AMP version.
-	 *
-	 * @since 0.2
-	 */
-	public static $tag = 'iframe';
-
-	/**
-	 * Default args.
-	 *
-	 * @var array
-	 */
-	protected $DEFAULT_ARGS = array(
-		'add_placeholder' => false,
-	);
-
-	/**
-	 * Get mapping of HTML selectors to the AMP component selectors which they may be converted into.
-	 *
-	 * @return array Mapping.
-	 */
-	public function get_selector_conversion_mapping() {
-		return array(
-			'iframe' => array(
-				'amp-iframe',
-			),
-		);
-	}
-
-	/**
-	 * Sanitize the <iframe> elements from the HTML contained in this instance's DOMDocument.
-	 *
-	 * @since 0.2
-	 */
-	public function sanitize() {
-		$nodes     = $this->dom->getElementsByTagName( self::$tag );
-		$num_nodes = $nodes->length;
-		if ( 0 === $num_nodes ) {
-			return;
-		}
-
-		for ( $i = $num_nodes - 1; $i >= 0; $i-- ) {
-			$node           = $nodes->item( $i );
-			$normalized_attributes = $this->normalize_attributes( AMP_DOM_Utils::get_node_attributes_as_assoc_array( $node ) );
-
-			/**
-			 * If the src doesn't exist, remove the node. Either it never
-			 * existed or was invalidated while filtering attributes above.
-			 *
-			 * @todo: add a filter to allow for a fallback element in this instance.
-			 * @see: https://github.com/ampproject/amphtml/issues/2261
-			 */
-			if ( empty( $normalized_attributes['src'] ) ) {
-				$this->remove_invalid_child( $node );
-				continue;
-			}
-
-			$this->did_convert_elements = true;
-			$normalized_attributes      = $this->set_layout( $normalized_attributes );
-			if ( empty( $normalized_attributes['layout'] ) && ! empty( $normalized_attributes['width'] ) && ! empty( $normalized_attributes['height'] ) ) {
-				$normalized_attributes['layout'] = 'intrinsic';
-				$this->add_or_append_attribute( $normalized_attributes, 'class', 'amp-wp-enforced-sizes' );
-			}
-
-			$new_node = AMP_DOM_Utils::create_node( $this->dom, 'amp-iframe', $normalized_attributes );
-
-			if ( true === $this->args['add_placeholder'] ) {
-				$placeholder_node = $this->build_placeholder( $normalized_attributes );
-				$new_node->appendChild( $placeholder_node );
-			}
-
-			$node->parentNode->replaceChild( $new_node, $node );
-		}
-	}
-
-	/**
-	 * Normalize HTML attributes for <amp-iframe> elements.
-	 *
-	 *
-	 * @param string[] $attributes {
-	 *      Attributes.
-	 *
-	 *      @type string $src IFrame URL - Empty if HTTPS required per $this->args['require_https_src']
-	 *      @type int $width <iframe> width attribute - Set to numeric value if px or %
-	 *      @type int $height <iframe> width attribute - Set to numeric value if px or %
-	 *      @type string $sandbox <iframe> `sandbox` attribute - Pass along if found; default to value of self::SANDBOX_DEFAULTS
-	 *      @type string $class <iframe> `class` attribute - Pass along if found
-	 *      @type string $sizes <iframe> `sizes` attribute - Pass along if found
-	 *      @type string $id <iframe> `id` attribute - Pass along if found
-	 *      @type int $frameborder <iframe> `frameborder` attribute - Filter to '0' or '1'; default to '0'
-	 *      @type bool $allowfullscreen <iframe> `allowfullscreen` attribute - Convert 'false' to empty string ''
-	 *      @type bool $allowtransparency <iframe> `allowtransparency` attribute - Convert 'false' to empty string ''
-	 * }
-	 * @return array Returns HTML attributes; normalizes src, dimensions, frameborder, sandox, allowtransparency and allowfullscreen
-	 */
-	private function normalize_attributes( $attributes ) {
-		$out = array();
-
-		foreach ( $attributes as $name => $value ) {
-			switch ( $name ) {
-				case 'src':
-					$out[ $name ] = $this->maybe_enforce_https_src( $value, true );
-					break;
-
-				case 'width':
-				case 'height':
-					$out[ $name ] = $this->sanitize_dimension( $value, $name );
-					break;
-
-				case 'frameborder':
-					if ( '0' !== $value && '1' !== $value ) {
-						$value = '0';
-					}
-					$out[ $name ] = $value;
-					break;
-
-				case 'allowfullscreen':
-				case 'allowtransparency':
-					if ( 'false' !== $value ) {
-						$out[ $name ] = '';
-					}
-					break;
-
-				default:
-					$out[ $name ] = $value;
-					break;
-			}
-		}
-
-		if ( ! isset( $out['sandbox'] ) ) {
-			$out['sandbox'] = self::SANDBOX_DEFAULTS;
-		}
-
-		return $out;
-	}
-
-	/**
-	 * Builds a DOMElement to use as a placeholder for an <iframe>.
-	 *
-	 * Important: The element returned must not be block-level (e.g. div) as the PHP DOM parser
-	 * will move it out from inside any containing paragraph. So this is why a span is used.
-	 *
-	 * @since 0.2
-	 *
-	 * @param string[] $parent_attributes {
-	 *      Attributes.
-	 *
-	 *      @type string $placeholder AMP HTML <amp-iframe> `placeholder` attribute; default to 'amp-wp-iframe-placeholder'
-	 *      @type string $class AMP HTML <amp-iframe> `class` attribute; default to 'amp-wp-iframe-placeholder'
-	 * }
-	 * @return DOMElement|false
-	 */
-	private function build_placeholder( $parent_attributes ) {
-		$placeholder_node = AMP_DOM_Utils::create_node( $this->dom, 'span', array(
-			'placeholder' => '',
-			'class'       => 'amp-wp-iframe-placeholder',
-		) );
-
-		return $placeholder_node;
-	}
-
-}
diff --git a/includes/sanitizers/class-amp-img-sanitizer.php b/includes/sanitizers/class-amp-img-sanitizer.php
deleted file mode 100644
index 9252b7139f8..00000000000
--- a/includes/sanitizers/class-amp-img-sanitizer.php
+++ /dev/null
@@ -1,376 +0,0 @@
-<?php
-/**
- * Class AMP_Img_Sanitizer.
- *
- * @package AMP
- */
-
-/**
- * Class AMP_Img_Sanitizer
- *
- * Converts <img> tags to <amp-img> or <amp-anim>
- */
-class AMP_Img_Sanitizer extends AMP_Base_Sanitizer {
-
-	/**
-	 * Value used for width attribute when $attributes['width'] is empty.
-	 *
-	 * @since 0.2
-	 *
-	 * @const int
-	 */
-	const FALLBACK_WIDTH = 600;
-
-	/**
-	 * Value used for height attribute when $attributes['height'] is empty.
-	 *
-	 * @since 0.2
-	 *
-	 * @const int
-	 */
-	const FALLBACK_HEIGHT = 400;
-
-	/**
-	 * Tag.
-	 *
-	 * @var string HTML <img> tag to identify and replace with AMP version.
-	 *
-	 * @since 0.2
-	 */
-	public static $tag = 'img';
-
-	/**
-	 * Animation extension.
-	 *
-	 * @var string
-	 */
-	private static $anim_extension = '.gif';
-
-	/**
-	 * Get mapping of HTML selectors to the AMP component selectors which they may be converted into.
-	 *
-	 * @return array Mapping.
-	 */
-	public function get_selector_conversion_mapping() {
-		return array(
-			'img' => array(
-				'amp-img',
-				'amp-anim',
-			),
-		);
-	}
-
-	/**
-	 * Sanitize the <img> elements from the HTML contained in this instance's DOMDocument.
-	 *
-	 * @since 0.2
-	 */
-	public function sanitize() {
-
-		/**
-		 * Node list.
-		 *
-		 * @var DOMNodeList $node
-		 */
-		$nodes           = $this->dom->getElementsByTagName( self::$tag );
-		$need_dimensions = array();
-
-		$num_nodes = $nodes->length;
-
-		if ( 0 === $num_nodes ) {
-			return;
-		}
-
-		for ( $i = $num_nodes - 1; $i >= 0; $i-- ) {
-			$node = $nodes->item( $i );
-			if ( ! $node instanceof DOMElement ) {
-				continue;
-			}
-
-			if ( ! $node->hasAttribute( 'src' ) || '' === trim( $node->getAttribute( 'src' ) ) ) {
-				$this->remove_invalid_child( $node );
-				continue;
-			}
-
-			// Determine which images need their dimensions determined/extracted.
-			if ( ! is_numeric( $node->getAttribute( 'width' ) ) || ! is_numeric( $node->getAttribute( 'height' ) ) ) {
-				$need_dimensions[ $node->getAttribute( 'src' ) ][] = $node;
-			} else {
-				$this->adjust_and_replace_node( $node );
-			}
-		}
-
-		$this->determine_dimensions( $need_dimensions );
-		$this->adjust_and_replace_nodes_in_array_map( $need_dimensions );
-	}
-
-	/**
-	 * "Filter" HTML attributes for <amp-anim> elements.
-	 *
-	 * @since 0.2
-	 *
-	 * @param string[] $attributes {
-	 *      Attributes.
-	 *
-	 *      @type string $src Image URL - Pass along if found
-	 *      @type string $alt <img> `alt` attribute - Pass along if found
-	 *      @type string $class <img> `class` attribute - Pass along if found
-	 *      @type string $srcset <img> `srcset` attribute - Pass along if found
-	 *      @type string $sizes <img> `sizes` attribute - Pass along if found
-	 *      @type string $on <img> `on` attribute - Pass along if found
-	 *      @type string $attribution <img> `attribution` attribute - Pass along if found
-	 *      @type int $width <img> width attribute - Set to numeric value if px or %
-	 *      @type int $height <img> width attribute - Set to numeric value if px or %
-	 * }
-	 * @return array Returns HTML attributes; removes any not specifically declared above from input.
-	 */
-	private function filter_attributes( $attributes ) {
-		$out = array();
-
-		foreach ( $attributes as $name => $value ) {
-			switch ( $name ) {
-				case 'width':
-				case 'height':
-					$out[ $name ] = $this->sanitize_dimension( $value, $name );
-					break;
-
-				case 'data-amp-layout':
-					$out['layout'] = $value;
-					break;
-
-				case 'data-amp-noloading':
-					$out['noloading'] = $value;
-					break;
-
-				default:
-					$out[ $name ] = $value;
-					break;
-			}
-		}
-
-		return $out;
-	}
-
-	/**
-	 * Determine width and height attribute values for images without them.
-	 *
-	 * Attempt to determine actual dimensions, otherwise set reasonable defaults.
-	 *
-	 * @param DOMElement[][] $need_dimensions Map <img> @src URLs to node for images with missing dimensions.
-	 */
-	private function determine_dimensions( $need_dimensions ) {
-
-		$dimensions_by_url = AMP_Image_Dimension_Extractor::extract( array_keys( $need_dimensions ) );
-
-		foreach ( $dimensions_by_url as $url => $dimensions ) {
-			foreach ( $need_dimensions[ $url ] as $node ) {
-				if ( ! $node instanceof DOMElement ) {
-					continue;
-				}
-				$class = $node->getAttribute( 'class' );
-				if ( ! $class ) {
-					$class = '';
-				}
-				if ( ! $dimensions ) {
-					$class .= ' amp-wp-unknown-size';
-				}
-
-				$width  = isset( $this->args['content_max_width'] ) ? $this->args['content_max_width'] : self::FALLBACK_WIDTH;
-				$height = self::FALLBACK_HEIGHT;
-				if ( isset( $dimensions['width'] ) ) {
-					$width = $dimensions['width'];
-				}
-				if ( isset( $dimensions['height'] ) ) {
-					$height = $dimensions['height'];
-				}
-
-				if ( ! is_numeric( $node->getAttribute( 'width' ) ) ) {
-
-					// Let width have the right aspect ratio based on the height attribute.
-					if ( is_numeric( $node->getAttribute( 'height' ) ) && isset( $dimensions['height'] ) && isset( $dimensions['width'] ) ) {
-						$width = ( floatval( $node->getAttribute( 'height' ) ) * $dimensions['width'] ) / $dimensions['height'];
-					}
-
-					$node->setAttribute( 'width', $width );
-					if ( ! isset( $dimensions['width'] ) ) {
-						$class .= ' amp-wp-unknown-width';
-					}
-				}
-				if ( ! is_numeric( $node->getAttribute( 'height' ) ) ) {
-
-					// Let height have the right aspect ratio based on the width attribute.
-					if ( is_numeric( $node->getAttribute( 'width' ) ) && isset( $dimensions['width'] ) && isset( $dimensions['height'] ) ) {
-						$height = ( floatval( $node->getAttribute( 'width' ) ) * $dimensions['height'] ) / $dimensions['width'];
-					}
-
-					$node->setAttribute( 'height', $height );
-					if ( ! isset( $dimensions['height'] ) ) {
-						$class .= ' amp-wp-unknown-height';
-					}
-				}
-				$node->setAttribute( 'class', trim( $class ) );
-			}
-		}
-	}
-
-	/**
-	 * Now that all images have width and height attributes, make final tweaks and replace original image nodes
-	 *
-	 * @param DOMNodeList[] $node_lists Img DOM nodes (now with width and height attributes).
-	 */
-	private function adjust_and_replace_nodes_in_array_map( $node_lists ) {
-		foreach ( $node_lists as $node_list ) {
-			foreach ( $node_list as $node ) {
-				$this->adjust_and_replace_node( $node );
-			}
-		}
-	}
-
-	/**
-	 * Make final modifications to DOMNode
-	 *
-	 * @param DOMElement $node The DOMNode to adjust and replace.
-	 */
-	private function adjust_and_replace_node( $node ) {
-
-		$amp_data       = $this->get_data_amp_attributes( $node );
-		$old_attributes = AMP_DOM_Utils::get_node_attributes_as_assoc_array( $node );
-		$old_attributes = $this->filter_data_amp_attributes( $old_attributes, $amp_data );
-		$old_attributes = $this->maybe_add_lightbox_attributes( $old_attributes, $node );
-
-		$new_attributes = $this->filter_attributes( $old_attributes );
-		$layout         = isset( $amp_data['layout'] ) ? $amp_data['layout'] : false;
-		$new_attributes = $this->filter_attachment_layout_attributes( $node, $new_attributes, $layout );
-
-		$this->add_or_append_attribute( $new_attributes, 'class', 'amp-wp-enforced-sizes' );
-		if ( empty( $new_attributes['layout'] ) && ! empty( $new_attributes['height'] ) && ! empty( $new_attributes['width'] ) ) {
-			$new_attributes['layout'] = 'intrinsic';
-		}
-
-		if ( $this->is_gif_url( $new_attributes['src'] ) ) {
-			$this->did_convert_elements = true;
-
-			$new_tag = 'amp-anim';
-		} else {
-			$new_tag = 'amp-img';
-		}
-		$new_node = AMP_DOM_Utils::create_node( $this->dom, $new_tag, $new_attributes );
-		$new_node = $this->handle_centering( $new_node );
-		$node->parentNode->replaceChild( $new_node, $node );
-		$this->add_auto_width_to_figure( $new_node );
-	}
-
-	/**
-	 * Set lightbox attributes.
-	 *
-	 * @param array   $attributes Array of attributes.
-	 * @param DomNode $node Array of AMP attributes.
-	 * @return array Updated attributes.
-	 */
-	private function maybe_add_lightbox_attributes( $attributes, $node ) {
-		$parent_node = $node->parentNode;
-		if ( ! ( $parent_node instanceof DOMElement ) || 'figure' !== $parent_node->tagName ) {
-			return $attributes;
-		}
-
-		$parent_attributes = AMP_DOM_Utils::get_node_attributes_as_assoc_array( $parent_node );
-
-		if ( isset( $parent_attributes['data-amp-lightbox'] ) && true === filter_var( $parent_attributes['data-amp-lightbox'], FILTER_VALIDATE_BOOLEAN ) ) {
-			$attributes['data-amp-lightbox'] = '';
-			$attributes['on']                = 'tap:' . self::AMP_IMAGE_LIGHTBOX_ID;
-			$attributes['role']              = 'button';
-			$attributes['tabindex']          = 0;
-
-			$this->maybe_add_amp_image_lightbox_node();
-		}
-
-		return $attributes;
-	}
-
-	/**
-	 * Determines is a URL is considered a GIF URL
-	 *
-	 * @since 0.2
-	 *
-	 * @param string $url URL to inspect for GIF vs. JPEG or PNG.
-	 *
-	 * @return bool Returns true if $url ends in `.gif`
-	 */
-	private function is_gif_url( $url ) {
-		$ext  = self::$anim_extension;
-		$path = wp_parse_url( $url, PHP_URL_PATH );
-		return substr( $path, -strlen( $ext ) ) === $ext;
-	}
-
-	/**
-	 * Handles an issue with the aligncenter class.
-	 *
-	 * If the <amp-img> has the class aligncenter, this strips the class and wraps it in a <figure> to center the image.
-	 * There was an issue where the aligncenter class overrode the "display: inline-block" rule of AMP's layout="intrinsic" attribute.
-	 * So this strips that class, and instead wraps the image in a <figure> to center it.
-	 *
-	 * @since 0.7
-	 * @see https://github.com/Automattic/amp-wp/issues/1104
-	 *
-	 * @param DOMElement $node The <amp-img> node.
-	 * @return DOMElement $node The <amp-img> node, possibly wrapped in a <figure>.
-	 */
-	public function handle_centering( $node ) {
-		$align_class = 'aligncenter';
-		$classes     = $node->getAttribute( 'class' );
-		$width       = $node->getAttribute( 'width' );
-
-		// If this doesn't have a width attribute, centering it in the <figure> wrapper won't work.
-		if ( empty( $width ) || ! in_array( $align_class, preg_split( '/\s+/', trim( $classes ) ), true ) ) {
-			return $node;
-		}
-
-		// Strip the class, and wrap the <amp-img> in a <figure>.
-		$classes = trim( str_replace( $align_class, '', $classes ) );
-		$node->setAttribute( 'class', $classes );
-		$figure = AMP_DOM_Utils::create_node(
-			$this->dom,
-			'figure',
-			array(
-				'class' => $align_class,
-				'style' => "max-width: {$width}px;",
-			)
-		);
-		$figure->appendChild( $node );
-
-		return $figure;
-	}
-
-	/**
-	 * Add an inline style to set the `<figure>` element's width to `auto` instead of `fit-content`.
-	 *
-	 * @since 1.0
-	 * @see https://github.com/Automattic/amp-wp/issues/1086
-	 *
-	 * @param DOMElement $node The DOMNode to adjust and replace.
-	 */
-	protected function add_auto_width_to_figure( $node ) {
-		$figure = $node->parentNode;
-		if ( ! ( $figure instanceof DOMElement ) || 'figure' !== $figure->tagName ) {
-			return;
-		}
-
-		$class = $figure->getAttribute( 'class' );
-		// Target only the <figure> with a 'wp-block-image' class attribute.
-		if ( false === strpos( $class, 'wp-block-image' ) ) {
-			return;
-		}
-
-		// Target only <figure> without a 'is-resized' class attribute.
-		if ( false !== strpos( $class, 'is-resized' ) ) {
-			return;
-		}
-
-		$new_style = 'width: auto;';
-		if ( $figure->hasAttribute( 'style' ) ) {
-			$figure->setAttribute( 'style', $new_style . $figure->getAttribute( 'style' ) );
-		} else {
-			$figure->setAttribute( 'style', $new_style );
-		}
-	}
-}
diff --git a/includes/sanitizers/class-amp-o2-player-sanitizer.php b/includes/sanitizers/class-amp-o2-player-sanitizer.php
deleted file mode 100644
index 0d594f8a7af..00000000000
--- a/includes/sanitizers/class-amp-o2-player-sanitizer.php
+++ /dev/null
@@ -1,140 +0,0 @@
-<?php
-/**
- * Class AMP_O2_Player_Sanitizer
- *
- * @package AMP
- */
-
-/**
- * Class AMP_O2_Player_Sanitizer
- *
- * Converts <div class="vdb_player><script></script></div> embed to <amp-o2-player>
- *
- * @since 1.0
- * @see https://www.ampproject.org/docs/reference/components/amp-o2-player
- */
-class AMP_O2_Player_Sanitizer extends AMP_Base_Sanitizer {
-	/**
-	 * Pattern to extract the information required for amp-o2-player element: data-pid, data-vid, data-bcid.
-	 *
-	 * @since 1.0
-	 */
-	const URL_PATTERN = '#.*delivery.vidible.tv\/jsonp\/pid=(?<data_pid>.*)\/vid=(?<data_vid>.*)\/(?<data_bcid>.*).js.*#i';
-
-	/**
-	 * AMP Tag.
-	 *
-	 * @since 1.0
-	 * @var string AMP Tag.
-	 */
-	private static $amp_tag = 'amp-o2-player';
-
-	/**
-	 * Amp O2 Player class.
-	 *
-	 * @since 1.0
-	 * @var string CSS class to identify O2 Player <div> to replace with AMP version.
-	 */
-	private static $xpath_selector = '//div[ contains( @class, \'vdb_player\' ) ]/script';
-
-	/**
-	 * Height to set for O2 Player elements.
-	 *
-	 * @since 1.0
-	 * @var string
-	 */
-	private static $height = '270';
-
-	/**
-	 * Width to set for O2 Player elements.
-	 *
-	 * @since 1.0
-	 * @var string
-	 */
-	private static $width = '480';
-
-	/**
-	 * Sanitize the O2 Player elements from the HTML contained in this instance's DOMDocument.
-	 *
-	 * @since 1.0
-	 */
-	public function sanitize() {
-		/**
-		 * XPath.
-		 *
-		 * @var DOMXPath $xpath
-		 */
-		$xpath = new DOMXPath( $this->dom );
-
-		/**
-		 * Node list.
-		 *
-		 * @var DOMNodeList $nodes
-		 */
-		$nodes     = $xpath->query( self::$xpath_selector );
-		$num_nodes = $nodes->length;
-
-		if ( 0 === $num_nodes ) {
-			return;
-		}
-
-		for ( $i = $num_nodes - 1; $i >= 0; $i-- ) {
-			$node = $nodes->item( $i );
-
-			$this->create_amp_o2_player( $this->dom, $node );
-		}
-
-	}
-
-	/**
-	 * Replaces node with amp-o2-player
-	 *
-	 * @since 1.0
-	 * @param DOMDocument $dom  The HTML Document.
-	 * @param DOMElement  $node The DOMNode to adjust and replace.
-	 */
-	private function create_amp_o2_player( $dom, $node ) {
-		$o2_attributes = $this->get_o2_player_attributes( $node->getAttribute( 'src' ) );
-
-		if ( ! empty( $o2_attributes ) ) {
-			$component_attributes = array_merge(
-				$o2_attributes, array(
-					'data-macros' => 'm.playback=click',
-					'layout'      => 'responsive',
-					'width'       => self::$width,
-					'height'      => self::$height,
-				)
-			);
-
-			$amp_o2_player = AMP_DOM_Utils::create_node( $dom, self::$amp_tag, $component_attributes );
-
-			$parent_node = $node->parentNode;
-
-			// replaces the wrapper that contains the script with amp-o2-player element.
-			$parent_node->parentNode->replaceChild( $amp_o2_player, $parent_node );
-
-			$this->did_convert_elements = true;
-		}
-	}
-
-	/**
-	 * Gets O2 Player's required attributes from script src
-	 *
-	 * @since 1.0
-	 * @param string $src Script src.
-	 *
-	 * @return array The data-* attributes for o2 player.
-	 */
-	private function get_o2_player_attributes( $src ) {
-		$found = preg_match( self::URL_PATTERN, $src, $matches );
-		if ( $found ) {
-			return array(
-				'data-pid'  => $matches['data_pid'],
-				'data-vid'  => $matches['data_vid'],
-				'data-bcid' => $matches['data_bcid'],
-			);
-		}
-		return array();
-	}
-
-}
diff --git a/includes/sanitizers/class-amp-playbuzz-sanitizer.php b/includes/sanitizers/class-amp-playbuzz-sanitizer.php
deleted file mode 100644
index 3ec07e5f8b9..00000000000
--- a/includes/sanitizers/class-amp-playbuzz-sanitizer.php
+++ /dev/null
@@ -1,146 +0,0 @@
-<?php
-/**
- * Class AMP_Playbuzz_Sanitizer
- *
- * @package AMP
- */
-
-/**
- * Class AMP_Playbuzz_Sanitizer
- *
- * Converts Playbuzz embed to <amp-playbuzz>
- *
- * @see https://www.playbuzz.com/
- */
-class AMP_Playbuzz_Sanitizer extends AMP_Base_Sanitizer {
-
-	/**
-	 * Tag.
-	 *
-	 * @var string HTML tag to identify and replace with AMP version.
-	 * @since 0.2
-	 */
-	public static $tag = 'div';
-
-	/**
-	 * PlayBuzz class.
-	 *
-	 * @var string CSS class to identify Playbuzz <div> to replace with AMP version.
-	 *
-	 * @since 0.2
-	 */
-	public static $pb_class = 'pb_feed';
-
-	/**
-	 * Hardcoded height to set for Playbuzz elements.
-	 *
-	 * @var string
-	 *
-	 * @since 0.2
-	 */
-	private static $height = '500';
-
-	/**
-	 * Get mapping of HTML selectors to the AMP component selectors which they may be converted into.
-	 *
-	 * @return array Mapping.
-	 */
-	public function get_selector_conversion_mapping() {
-		return array(
-			'div.pb_feed' => array( 'amp-playbuzz.pb_feed' ),
-		);
-	}
-
-	/**
-	 * Sanitize the Playbuzz elements from the HTML contained in this instance's DOMDocument.
-	 *
-	 * @since 0.2
-	 */
-	public function sanitize() {
-
-		$nodes     = $this->dom->getElementsByTagName( self::$tag );
-		$num_nodes = $nodes->length;
-
-		if ( 0 === $num_nodes ) {
-			return;
-		}
-
-		for ( $i = $num_nodes - 1; $i >= 0; $i-- ) {
-			$node = $nodes->item( $i );
-
-			if ( self::$pb_class !== $node->getAttribute( 'class' ) ) {
-				continue;
-			}
-
-			$old_attributes = AMP_DOM_Utils::get_node_attributes_as_assoc_array( $node );
-
-			$new_attributes = $this->filter_attributes( $old_attributes );
-
-			if ( ! isset( $new_attributes['data-item'] ) && ! isset( $new_attributes['src'] ) ) {
-				continue;
-			}
-
-			$new_node = AMP_DOM_Utils::create_node( $this->dom, 'amp-playbuzz', $new_attributes );
-
-			$node->parentNode->replaceChild( $new_node, $node );
-
-			$this->did_convert_elements = true;
-
-		}
-
-	}
-
-	/**
-	 * "Filter" HTML attributes for <amp-audio> elements.
-	 *
-	 * @since 0.2
-	 *
-	 * @param string[] $attributes {
-	 *      Attributes.
-	 *
-	 *      @type string $data-item Playbuzz <div> attribute - Pass along if found and not empty.
-	 *      @type string $data-game Playbuzz <div> attribute - Assign to its value to $attributes['src'] if found and not empty.
-	 *      @type string $data-game-info Playbuzz <div> attribute - Assign to its value to $attributes['data-item-info'] if found.
-	 *      @type string $data-shares Playbuzz <div> attribute - Assign to its value to $attributes['data-share-buttons'] if found.
-	 *      @type string $data-comments Playbuzz <div> attribute - Pass along if found.
-	 *      @type int $height Playbuzz <div> attribute - Set to hardcoded value of 500.
-	 * }
-	 * @return array Returns HTML attributes; removes any not specifically declared above from input.
-	 */
-	private function filter_attributes( $attributes ) {
-		$out = array();
-
-		foreach ( $attributes as $name => $value ) {
-			switch ( $name ) {
-				case 'data-item':
-					if ( ! empty( $value ) ) {
-						$out['data-item'] = $value;
-					}
-					break;
-
-				case 'data-game':
-					if ( ! empty( $value ) ) {
-						$out['src'] = $value;
-					}
-					break;
-
-				case 'data-shares':
-					$out['data-share-buttons'] = $value;
-					break;
-
-				case 'data-game-info':
-				case 'data-comments':
-				case 'class':
-					$out[ $name ] = $value;
-					break;
-
-				default:
-					break;
-			}
-		}
-
-		$out['height'] = self::$height;
-
-		return $out;
-	}
-}
diff --git a/includes/sanitizers/class-amp-rule-spec.php b/includes/sanitizers/class-amp-rule-spec.php
deleted file mode 100644
index a09fb94eb5b..00000000000
--- a/includes/sanitizers/class-amp-rule-spec.php
+++ /dev/null
@@ -1,139 +0,0 @@
-<?php
-/**
- * Class AMP_Rule_Spec
- *
- * @package AMP
- */
-
-/**
- * Class AMP_Rule_Spec
- *
- * Set of constants used throughout the sanitizer.
- */
-abstract class AMP_Rule_Spec {
-
-	/**
-	 * AMP rule_spec types
-	 */
-	const ATTR_SPEC_LIST = 'attr_spec_list';
-	const TAG_SPEC       = 'tag_spec';
-	const CDATA          = 'cdata';
-
-	/**
-	 * AMP attr_spec value check results.
-	 *
-	 * In 0.7 these changed from strings to integers to speed up comparisons.
-	 */
-	const PASS           = 1;
-	const FAIL           = 0;
-	const NOT_APPLICABLE = -1;
-
-	/**
-	 * HTML Element Tag rule names
-	 */
-	const DISALLOWED_ANCESTOR = 'disallowed_ancestor';
-	const MANDATORY_ANCESTOR  = 'mandatory_ancestor';
-	const MANDATORY_PARENT    = 'mandatory_parent';
-
-	/**
-	 * HTML Element Attribute rule names
-	 */
-	const ALLOW_EMPTY             = 'allow_empty';
-	const ALLOW_RELATIVE          = 'allow_relative';
-	const ALLOWED_PROTOCOL        = 'protocol';
-	const ALTERNATIVE_NAMES       = 'alternative_names';
-	const BLACKLISTED_VALUE_REGEX = 'blacklisted_value_regex';
-	const DISALLOWED_DOMAIN       = 'disallowed_domain';
-	const MANDATORY               = 'mandatory';
-	const VALUE                   = 'value';
-	const VALUE_CASEI             = 'value_casei';
-	const VALUE_REGEX             = 'value_regex';
-	const VALUE_REGEX_CASEI       = 'value_regex_casei';
-	const VALUE_PROPERTIES        = 'value_properties';
-	const VALUE_URL               = 'value_url';
-
-	/**
-	 * Supported layout values.
-	 *
-	 * @since 1.0
-	 * @var array
-	 */
-	public static $layout_enum = array(
-		1 => 'nodisplay',
-		2 => 'fixed',
-		3 => 'fixed-height',
-		4 => 'responsive',
-		5 => 'container',
-		6 => 'fill',
-		7 => 'flex-item',
-		8 => 'fluid',
-		9 => 'intrinsic',
-	);
-
-	/**
-	 * List of boolean attributes.
-	 *
-	 * @since 0.7
-	 * @var array
-	 */
-	public static $boolean_attributes = array(
-		'allowfullscreen',
-		'async',
-		'autofocus',
-		'autoplay',
-		'checked',
-		'compact',
-		'controls',
-		'declare',
-		'default',
-		'defaultchecked',
-		'defaultmuted',
-		'defaultselected',
-		'defer',
-		'disabled',
-		'draggable',
-		'enabled',
-		'formnovalidate',
-		'hidden',
-		'indeterminate',
-		'inert',
-		'ismap',
-		'itemscope',
-		'loop',
-		'multiple',
-		'muted',
-		'nohref',
-		'noresize',
-		'noshade',
-		'novalidate',
-		'nowrap',
-		'open',
-		'pauseonexit',
-		'readonly',
-		'required',
-		'reversed',
-		'scoped',
-		'seamless',
-		'selected',
-		'sortable',
-		'spellcheck',
-		'translate',
-		'truespeed',
-		'typemustmatch',
-		'visible',
-	);
-
-	/**
-	 * Additional allowed tags.
-	 *
-	 * @var array
-	 */
-	public static $additional_allowed_tags = array(
-
-		// An experimental tag with no protoascii.
-		'amp-share-tracking' => array(
-			'attr_spec_list' => array(),
-			'tag_spec'       => array(),
-		),
-	);
-}
diff --git a/includes/sanitizers/class-amp-script-sanitizer.php b/includes/sanitizers/class-amp-script-sanitizer.php
deleted file mode 100644
index 1e39e1cf394..00000000000
--- a/includes/sanitizers/class-amp-script-sanitizer.php
+++ /dev/null
@@ -1,49 +0,0 @@
-<?php
-/**
- * Class AMP_Script_Sanitizer
- *
- * @since 1.0
- * @package AMP
- */
-
-/**
- * Class AMP_Script_Sanitizer
- *
- * @since 1.0
- */
-class AMP_Script_Sanitizer extends AMP_Base_Sanitizer {
-
-	/**
-	 * Sanitize noscript elements.
-	 *
-	 * Eventually this should also handle script elements, if there is a known AMP equivalent.
-	 * If nothing is done with script elements, the whitelist sanitizer will deal with them ultimately.
-	 *
-	 * @todo Eventually this try to automatically convert script tags to AMP when they are recognized. See <https://github.com/Automattic/amp-wp/issues/1032>.
-	 * @todo When a script has an adjacent noscript, consider removing the script here to prevent validation error later. See <https://github.com/Automattic/amp-wp/issues/1213>.
-	 *
-	 * @since 1.0
-	 */
-	public function sanitize() {
-		$noscripts = $this->dom->getElementsByTagName( 'noscript' );
-
-		for ( $i = $noscripts->length - 1; $i >= 0; $i-- ) {
-			$noscript = $noscripts->item( $i );
-
-			// Skip AMP boilerplate.
-			if ( $noscript->firstChild instanceof DOMElement && $noscript->firstChild->hasAttribute( 'amp-boilerplate' ) ) {
-				continue;
-			}
-
-			$fragment = $this->dom->createDocumentFragment();
-			$fragment->appendChild( $this->dom->createComment( 'noscript' ) );
-			while ( $noscript->firstChild ) {
-				$fragment->appendChild( $noscript->firstChild );
-			}
-			$fragment->appendChild( $this->dom->createComment( '/noscript' ) );
-			$noscript->parentNode->replaceChild( $fragment, $noscript );
-
-			$this->did_convert_elements = true;
-		}
-	}
-}
diff --git a/includes/sanitizers/class-amp-style-sanitizer.php b/includes/sanitizers/class-amp-style-sanitizer.php
deleted file mode 100644
index 6993a472a51..00000000000
--- a/includes/sanitizers/class-amp-style-sanitizer.php
+++ /dev/null
@@ -1,2225 +0,0 @@
-<?php
-/**
- * Class AMP_Style_Sanitizer
- *
- * @package AMP
- */
-
-use \Sabberworm\CSS\RuleSet\DeclarationBlock;
-use \Sabberworm\CSS\CSSList\CSSList;
-use \Sabberworm\CSS\Property\Selector;
-use \Sabberworm\CSS\RuleSet\RuleSet;
-use \Sabberworm\CSS\Property\AtRule;
-use \Sabberworm\CSS\CSSList\KeyFrame;
-use \Sabberworm\CSS\RuleSet\AtRuleSet;
-use \Sabberworm\CSS\Property\Import;
-use \Sabberworm\CSS\CSSList\AtRuleBlockList;
-use \Sabberworm\CSS\Value\RuleValueList;
-use \Sabberworm\CSS\Value\URL;
-use \Sabberworm\CSS\CSSList\Document;
-
-/**
- * Class AMP_Style_Sanitizer
- *
- * Collects inline styles and outputs them in the amp-custom stylesheet.
- */
-class AMP_Style_Sanitizer extends AMP_Base_Sanitizer {
-
-	/**
-	 * Error code for tree shaking.
-	 *
-	 * @var string
-	 */
-	const TREE_SHAKING_ERROR_CODE = 'removed_unused_css_rules';
-
-	/**
-	 * Error code for illegal at-rule.
-	 *
-	 * @var string
-	 */
-	const ILLEGAL_AT_RULE_ERROR_CODE = 'illegal_css_at_rule';
-
-	/**
-	 * Inline style selector's specificity multiplier, i.e. used to generate the number of ':not(#_)' placeholders.
-	 *
-	 * @var int
-	 */
-	const INLINE_SPECIFICITY_MULTIPLIER = 5; // @todo The correctness of using "5" should be validated.
-
-	/**
-	 * Array of flags used to control sanitization.
-	 *
-	 * @var array {
-	 *      @type string   $remove_unused_rules        Enum 'never', 'sometimes' (default), 'always'. If total CSS is greater than max_bytes, whether to strip selectors (and then empty rules) when they are not found to be used in doc. A validation error will be emitted when stripping happens since it is not completely safe in the case of dynamic content.
-	 *      @type string[] $dynamic_element_selectors  Selectors for elements (or their ancestors) which contain dynamic content; selectors containing these will not be filtered.
-	 *      @type bool     $use_document_element       Whether the root of the document should be used rather than the body.
-	 *      @type bool     $require_https_src          Require HTTPS URLs.
-	 *      @type bool     $allow_dirty_styles         Allow dirty styles. This short-circuits the sanitize logic; it is used primarily in Customizer preview.
-	 *      @type callable $validation_error_callback  Function to call when a validation error is encountered.
-	 *      @type bool     $should_locate_sources      Whether to locate the sources when reporting validation errors.
-	 *      @type string   $parsed_cache_variant       Additional value by which to vary parsed cache.
-	 *      @type bool     $accept_tree_shaking        Whether to accept tree-shaking by default and bypass a validation error.
-	 * }
-	 */
-	protected $args;
-
-	/**
-	 * Default args.
-	 *
-	 * @var array
-	 */
-	protected $DEFAULT_ARGS = array(
-		'remove_unused_rules'       => 'sometimes',
-		'dynamic_element_selectors' => array(
-			'amp-list',
-			'amp-live-list',
-			'[submit-error]',
-			'[submit-success]',
-		),
-		'should_locate_sources'     => false,
-		'parsed_cache_variant'      => null,
-		'accept_tree_shaking'       => false,
-	);
-
-	/**
-	 * Stylesheets.
-	 *
-	 * Values are the CSS stylesheets. Keys are MD5 hashes of the stylesheets,
-	 *
-	 * @since 0.7
-	 * @var string[]
-	 */
-	private $stylesheets = array();
-
-	/**
-	 * List of stylesheet parts prior to selector/rule removal (tree shaking).
-	 *
-	 * Keys are MD5 hashes of stylesheets.
-	 *
-	 * @since 1.0
-	 * @var array[] {
-	 *     @type array              $stylesheet Array of stylesheet chunked, with declaration blocks being represented as arrays.
-	 *     @type DOMElement|DOMAttr $node       Origin for styles.
-	 *     @type array              $sources    Sources for the node.
-	 *     @type bool               $keyframes  Whether an amp-keyframes.
-	 * }
-	 */
-	private $pending_stylesheets = array();
-
-	/**
-	 * Spec for style[amp-custom] cdata.
-	 *
-	 * @since 1.0
-	 * @var array
-	 */
-	private $style_custom_cdata_spec;
-
-	/**
-	 * The style[amp-custom] element.
-	 *
-	 * @var DOMElement
-	 */
-	private $amp_custom_style_element;
-
-	/**
-	 * Spec for style[amp-keyframes] cdata.
-	 *
-	 * @since 1.0
-	 * @var array
-	 */
-	private $style_keyframes_cdata_spec;
-
-	/**
-	 * Regex for allowed font stylesheet URL.
-	 *
-	 * @var string
-	 */
-	private $allowed_font_src_regex;
-
-	/**
-	 * Base URL for styles.
-	 *
-	 * Full URL with trailing slash.
-	 *
-	 * @var string
-	 */
-	private $base_url;
-
-	/**
-	 * URL of the content directory.
-	 *
-	 * @var string
-	 */
-	private $content_url;
-
-	/**
-	 * Class names used in document.
-	 *
-	 * @since 1.0
-	 * @var array
-	 */
-	private $used_class_names = array();
-
-	/**
-	 * Tag names used in document.
-	 *
-	 * @since 1.0
-	 * @var array
-	 */
-	private $used_tag_names = array();
-
-	/**
-	 * XPath.
-	 *
-	 * @since 1.0
-	 * @var DOMXPath
-	 */
-	private $xpath;
-
-	/**
-	 * Amount of time that was spent parsing CSS.
-	 *
-	 * @since 1.0
-	 * @var float
-	 */
-	private $parse_css_duration = 0.0;
-
-	/**
-	 * THe HEAD element.
-	 *
-	 * @var DOMElement
-	 */
-	private $head;
-
-	/**
-	 * Current node being processed.
-	 *
-	 * @var DOMElement|DOMAttr
-	 */
-	private $current_node;
-
-	/**
-	 * Current sources for a given node.
-	 *
-	 * @var array
-	 */
-	private $current_sources;
-
-	/**
-	 * Log of the stylesheet URLs that have been imported to guard against infinite loops.
-	 *
-	 * @var array
-	 */
-	private $processed_imported_stylesheet_urls = array();
-
-	/**
-	 * List of font stylesheets that were @import'ed which should have been <link>'ed to instead.
-	 *
-	 * These font URLs will be cached with the parsed CSS and then converted into stylesheet links.
-	 *
-	 * @var array
-	 */
-	private $imported_font_urls = array();
-
-	/**
-	 * Mapping of HTML element selectors to AMP selector elements.
-	 *
-	 * @var array
-	 */
-	private $selector_mappings = array();
-
-	/**
-	 * Get error codes that can be raised during parsing of CSS.
-	 *
-	 * This is used to determine which validation errors should be taken into account
-	 * when determining which validation errors should vary the parse cache.
-	 *
-	 * @return array
-	 */
-	public static function get_css_parser_validation_error_codes() {
-		return array(
-			'css_parse_error',
-			'excessive_css',
-			self::ILLEGAL_AT_RULE_ERROR_CODE,
-			'illegal_css_important',
-			'illegal_css_property',
-			self::TREE_SHAKING_ERROR_CODE,
-			'unrecognized_css',
-			'disallowed_file_extension',
-			'file_path_not_found',
-		);
-	}
-
-	/**
-	 * AMP_Base_Sanitizer constructor.
-	 *
-	 * @since 0.7
-	 *
-	 * @param DOMDocument $dom  Represents the HTML document to sanitize.
-	 * @param array       $args Args.
-	 */
-	public function __construct( DOMDocument $dom, array $args = array() ) {
-		parent::__construct( $dom, $args );
-
-		foreach ( AMP_Allowed_Tags_Generated::get_allowed_tag( 'style' ) as $spec_rule ) {
-			if ( ! isset( $spec_rule[ AMP_Rule_Spec::TAG_SPEC ]['spec_name'] ) ) {
-				continue;
-			}
-			if ( 'style[amp-keyframes]' === $spec_rule[ AMP_Rule_Spec::TAG_SPEC ]['spec_name'] ) {
-				$this->style_keyframes_cdata_spec = $spec_rule[ AMP_Rule_Spec::CDATA ];
-			} elseif ( 'style amp-custom' === $spec_rule[ AMP_Rule_Spec::TAG_SPEC ]['spec_name'] ) {
-				$this->style_custom_cdata_spec = $spec_rule[ AMP_Rule_Spec::CDATA ];
-			}
-		}
-
-		$spec_name = 'link rel=stylesheet for fonts'; // phpcs:ignore WordPress.WP.EnqueuedResources.NonEnqueuedStylesheet
-		foreach ( AMP_Allowed_Tags_Generated::get_allowed_tag( 'link' ) as $spec_rule ) {
-			if ( isset( $spec_rule[ AMP_Rule_Spec::TAG_SPEC ]['spec_name'] ) && $spec_name === $spec_rule[ AMP_Rule_Spec::TAG_SPEC ]['spec_name'] ) {
-				$this->allowed_font_src_regex = '@^(' . $spec_rule[ AMP_Rule_Spec::ATTR_SPEC_LIST ]['href']['value_regex'] . ')$@';
-				break;
-			}
-		}
-
-		$guessurl = site_url();
-		if ( ! $guessurl ) {
-			$guessurl = wp_guess_url();
-		}
-		$this->base_url    = $guessurl;
-		$this->content_url = WP_CONTENT_URL;
-		$this->xpath       = new DOMXPath( $dom );
-	}
-
-	/**
-	 * Get list of CSS styles in HTML content of DOMDocument ($this->dom).
-	 *
-	 * @since 0.4
-	 * @deprecated As of 1.0, use get_stylesheets().
-	 *
-	 * @return array[] Mapping CSS selectors to array of properties, or mapping of keys starting with 'stylesheet:' with value being the stylesheet.
-	 */
-	public function get_styles() {
-		return array();
-	}
-
-	/**
-	 * Get stylesheets.
-	 *
-	 * @since 0.7
-	 * @returns array Values are the CSS stylesheets. Keys are MD5 hashes of the stylesheets.
-	 */
-	public function get_stylesheets() {
-		return $this->stylesheets;
-	}
-
-	/**
-	 * Get list of all the class names used in the document, including those used in [class] attributes.
-	 *
-	 * @since 1.0
-	 * @return array Used class names.
-	 */
-	private function get_used_class_names() {
-		if ( empty( $this->used_class_names ) ) {
-			$classes = ' ';
-			foreach ( $this->xpath->query( '//*/@class' ) as $class_attribute ) {
-				$classes .= ' ' . $class_attribute->nodeValue;
-			}
-
-			// Find all [class] attributes and capture the contents of any single- or double-quoted strings.
-			foreach ( $this->xpath->query( '//*/@' . AMP_DOM_Utils::get_amp_bind_placeholder_prefix() . 'class' ) as $bound_class_attribute ) {
-				if ( preg_match_all( '/([\'"])([^\1]*?)\1/', $bound_class_attribute->nodeValue, $matches ) ) {
-					$classes .= ' ' . implode( ' ', $matches[2] );
-				}
-			}
-
-			$this->used_class_names = array_unique( array_filter( preg_split( '/\s+/', trim( $classes ) ) ) );
-		}
-		return $this->used_class_names;
-	}
-
-
-	/**
-	 * Get list of all the tag names used in the document.
-	 *
-	 * @since 1.0
-	 * @return array Used tag names.
-	 */
-	private function get_used_tag_names() {
-		if ( empty( $this->used_tag_names ) ) {
-			$used_tag_names = array();
-			foreach ( $this->dom->getElementsByTagName( '*' ) as $el ) {
-				$used_tag_names[ $el->tagName ] = true;
-			}
-			$this->used_tag_names = array_keys( $used_tag_names );
-		}
-		return $this->used_tag_names;
-	}
-
-	/**
-	 * Run logic before any sanitizers are run.
-	 *
-	 * After the sanitizers are instantiated but before calling sanitize on each of them, this
-	 * method is called with list of all the instantiated sanitizers.
-	 *
-	 * @param AMP_Base_Sanitizer[] $sanitizers Sanitizers.
-	 */
-	public function init( $sanitizers ) {
-		parent::init( $sanitizers );
-
-		foreach ( $sanitizers as $sanitizer ) {
-			foreach ( $sanitizer->get_selector_conversion_mapping() as $html_selectors => $amp_selectors ) {
-				if ( ! isset( $this->selector_mappings[ $html_selectors ] ) ) {
-					$this->selector_mappings[ $html_selectors ] = $amp_selectors;
-				} else {
-					$this->selector_mappings[ $html_selectors ] = array_unique(
-						array_merge( $this->selector_mappings[ $html_selectors ], $amp_selectors )
-					);
-				}
-
-				// Prevent selectors like `amp-img img` getting deleted since `img` does not occur in the DOM.
-				$this->args['dynamic_element_selectors'] = array_merge(
-					$this->args['dynamic_element_selectors'],
-					$this->selector_mappings[ $html_selectors ]
-				);
-			}
-		}
-	}
-
-	/**
-	 * Sanitize CSS styles within the HTML contained in this instance's DOMDocument.
-	 *
-	 * @since 0.4
-	 */
-	public function sanitize() {
-		$elements = array();
-
-		// Do nothing if inline styles are allowed.
-		if ( ! empty( $this->args['allow_dirty_styles'] ) ) {
-			return;
-		}
-
-		$this->head = $this->dom->getElementsByTagName( 'head' )->item( 0 );
-		if ( ! $this->head ) {
-			$this->head = $this->dom->createElement( 'head' );
-			$this->dom->documentElement->insertBefore( $this->head, $this->dom->documentElement->firstChild );
-		}
-
-		$this->parse_css_duration = 0.0;
-
-		/*
-		 * Note that xpath is used to query the DOM so that the link and style elements will be
-		 * in document order. DOMNode::compareDocumentPosition() is not yet implemented.
-		 */
-		$xpath = $this->xpath;
-
-		$lower_case = 'translate( %s, "ABCDEFGHIJKLMNOPQRSTUVWXYZ", "abcdefghijklmnopqrstuvwxyz" )'; // In XPath 2.0 this is lower-case().
-		$predicates = array(
-			sprintf( '( self::style and not( @amp-boilerplate ) and ( not( @type ) or %s = "text/css" ) )', sprintf( $lower_case, '@type' ) ),
-			sprintf( '( self::link and @href and %s = "stylesheet" )', sprintf( $lower_case, '@rel' ) ),
-		);
-
-		foreach ( $xpath->query( '//*[ ' . implode( ' or ', $predicates ) . ' ]' ) as $element ) {
-			$elements[] = $element;
-		}
-
-		// If 'width' attribute is present for 'col' tag, convert to proper CSS rule.
-		foreach ( $this->dom->getElementsByTagName( 'col' ) as $col ) {
-			/**
-			 * Col element.
-			 *
-			 * @var DOMElement $col
-			 */
-			$width_attr = $col->getAttribute( 'width' );
-			if ( ! empty( $width_attr ) && ( false === strpos( $width_attr, '*' ) ) ) {
-				$width_style = 'width: ' . $width_attr;
-				if ( is_numeric( $width_attr ) ) {
-					$width_style .= 'px';
-				}
-				if ( $col->hasAttribute( 'style' ) ) {
-					$col->setAttribute( 'style', $width_style . ';' . $col->getAttribute( 'style' ) );
-				} else {
-					$col->setAttribute( 'style', $width_style );
-				}
-				$col->removeAttribute( 'width' );
-			}
-		}
-
-		/**
-		 * Element.
-		 *
-		 * @var DOMElement $element
-		 */
-		foreach ( $elements as $element ) {
-			$node_name = strtolower( $element->nodeName );
-			if ( 'style' === $node_name ) {
-				$this->process_style_element( $element );
-			} elseif ( 'link' === $node_name ) {
-				$this->process_link_element( $element );
-			}
-		}
-
-		$elements = array();
-		foreach ( $xpath->query( '//*[ @style ]' ) as $element ) {
-			$elements[] = $element;
-		}
-		foreach ( $elements as $element ) {
-			$this->collect_inline_styles( $element );
-		}
-
-		$this->finalize_styles();
-
-		$this->did_convert_elements = true;
-
-		if ( $this->parse_css_duration > 0.0 ) {
-			AMP_HTTP::send_server_timing( 'amp_parse_css', $this->parse_css_duration, 'AMP Parse CSS' );
-		}
-	}
-
-	/**
-	 * Generate a URL's fully-qualified file path.
-	 *
-	 * @since 0.7
-	 * @see WP_Styles::_css_href()
-	 *
-	 * @param string   $url The file URL.
-	 * @param string[] $allowed_extensions Allowed file extensions for local files.
-	 * @return string|WP_Error Style's absolute validated filesystem path, or WP_Error when error.
-	 */
-	public function get_validated_url_file_path( $url, $allowed_extensions = array() ) {
-		$needs_base_url = (
-			! is_bool( $url )
-			&&
-			! preg_match( '|^(https?:)?//|', $url )
-			&&
-			! ( $this->content_url && 0 === strpos( $url, $this->content_url ) )
-		);
-		if ( $needs_base_url ) {
-			$url = $this->base_url . $url;
-		}
-
-		$remove_url_scheme = function( $schemed_url ) {
-			return preg_replace( '#^\w+:(?=//)#', '', $schemed_url );
-		};
-
-		// Strip URL scheme, query, and fragment.
-		$url = $remove_url_scheme( preg_replace( ':[\?#].*$:', '', $url ) );
-
-		$includes_url = $remove_url_scheme( includes_url( '/' ) );
-		$content_url  = $remove_url_scheme( content_url( '/' ) );
-		$admin_url    = $remove_url_scheme( get_admin_url( null, '/' ) );
-
-		$allowed_hosts = array(
-			wp_parse_url( $includes_url, PHP_URL_HOST ),
-			wp_parse_url( $content_url, PHP_URL_HOST ),
-			wp_parse_url( $admin_url, PHP_URL_HOST ),
-		);
-
-		$url_host = wp_parse_url( $url, PHP_URL_HOST );
-
-		// Validate file extensions.
-		if ( ! empty( $allowed_extensions ) ) {
-			$pattern = sprintf( '/\.(%s)$/i', implode( '|', $allowed_extensions ) );
-			if ( ! preg_match( $pattern, $url ) ) {
-				/* translators: %s: the file URL. */
-				return new WP_Error( 'disallowed_file_extension', sprintf( __( 'File does not have an allowed file extension for filesystem access (%s).', 'amp' ), $url ) );
-			}
-		}
-
-		if ( ! in_array( $url_host, $allowed_hosts, true ) ) {
-			/* translators: %s: the file URL */
-			return new WP_Error( 'external_file_url', sprintf( __( 'URL is located on an external domain: %s.', 'amp' ), $url_host ) );
-		}
-
-		$base_path = null;
-		$file_path = null;
-		if ( 0 === strpos( $url, $content_url ) ) {
-			$base_path = WP_CONTENT_DIR;
-			$file_path = substr( $url, strlen( $content_url ) - 1 );
-		} elseif ( 0 === strpos( $url, $includes_url ) ) {
-			$base_path = ABSPATH . WPINC;
-			$file_path = substr( $url, strlen( $includes_url ) - 1 );
-		} elseif ( 0 === strpos( $url, $admin_url ) ) {
-			$base_path = ABSPATH . 'wp-admin';
-			$file_path = substr( $url, strlen( $admin_url ) - 1 );
-		}
-
-		if ( ! $file_path || false !== strpos( $file_path, '../' ) || false !== strpos( $file_path, '..\\' ) ) {
-			/* translators: %s: the file URL. */
-			return new WP_Error( 'file_path_not_allowed', sprintf( __( 'Disallowed URL filesystem path for %s.', 'amp' ), $url ) );
-		}
-		if ( ! file_exists( $base_path . $file_path ) ) {
-			/* translators: %s: the file URL. */
-			return new WP_Error( 'file_path_not_found', sprintf( __( 'Unable to locate filesystem path for %s.', 'amp' ), $url ) );
-		}
-
-		return $base_path . $file_path;
-	}
-
-	/**
-	 * Set the current node (and its sources when required).
-	 *
-	 * @since 1.0
-	 * @param DOMElement|DOMAttr|null $node Current node, or null to reset.
-	 */
-	private function set_current_node( $node ) {
-		if ( $this->current_node === $node ) {
-			return;
-		}
-
-		$this->current_node = $node;
-		if ( empty( $node ) ) {
-			$this->current_sources = null;
-		} elseif ( ! empty( $this->args['should_locate_sources'] ) ) {
-			$this->current_sources = AMP_Validation_Manager::locate_sources( $node );
-		}
-	}
-
-	/**
-	 * Process style element.
-	 *
-	 * @param DOMElement $element Style element.
-	 */
-	private function process_style_element( DOMElement $element ) {
-		$this->set_current_node( $element ); // And sources when needing to be located.
-
-		// @todo Any @keyframes rules could be removed from amp-custom and instead added to amp-keyframes.
-		$is_keyframes = $element->hasAttribute( 'amp-keyframes' );
-		$stylesheet   = trim( $element->textContent );
-		$cdata_spec   = $is_keyframes ? $this->style_keyframes_cdata_spec : $this->style_custom_cdata_spec;
-
-		// Honor the style's media attribute.
-		$media = $element->getAttribute( 'media' );
-		if ( $media && 'all' !== $media ) {
-			$stylesheet = sprintf( '@media %s { %s }', $media, $stylesheet );
-		}
-
-		$processed = $this->process_stylesheet( $stylesheet, array(
-			'allowed_at_rules'   => $cdata_spec['css_spec']['allowed_at_rules'],
-			'property_whitelist' => $cdata_spec['css_spec']['declaration'],
-			'validate_keyframes' => $cdata_spec['css_spec']['validate_keyframes'],
-		) );
-
-		$this->pending_stylesheets[] = array_merge(
-			array(
-				'keyframes' => $is_keyframes,
-				'node'      => $element,
-				'sources'   => $this->current_sources,
-			),
-			wp_array_slice_assoc( $processed, array( 'stylesheet', 'imported_font_urls' ) )
-		);
-
-		if ( $element->hasAttribute( 'amp-custom' ) ) {
-			if ( ! $this->amp_custom_style_element ) {
-				$this->amp_custom_style_element = $element;
-			} else {
-				$element->parentNode->removeChild( $element ); // There can only be one. #highlander.
-			}
-		} else {
-
-			// Remove from DOM since we'll be adding it to amp-custom.
-			$element->parentNode->removeChild( $element );
-		}
-
-		$this->set_current_node( null );
-	}
-
-	/**
-	 * Process link element.
-	 *
-	 * @param DOMElement $element Link element.
-	 */
-	private function process_link_element( DOMElement $element ) {
-		$href = $element->getAttribute( 'href' );
-
-		// Allow font URLs, including protocol-less URLs and recognized URLs that use HTTP instead of HTTPS.
-		$normalized_url = preg_replace( '#^(http:)?(?=//)#', 'https:', $href );
-		if ( $this->allowed_font_src_regex && preg_match( $this->allowed_font_src_regex, $normalized_url ) ) {
-			if ( $href !== $normalized_url ) {
-				$element->setAttribute( 'href', $normalized_url );
-			}
-
-			/*
-			 * Make sure rel=preconnect link is present for Google Fonts stylesheet.
-			 * Note that core themes normally do this already, per <https://core.trac.wordpress.org/ticket/37171>.
-			 * But not always, per <https://core.trac.wordpress.org/ticket/44668>.
-			 * This also ensures that other themes will get the preconnect link when
-			 * they don't implement the resource hint.
-			 */
-			$needs_preconnect_link = (
-				'https://fonts.googleapis.com/' === substr( $normalized_url, 0, 29 )
-				&&
-				0 === $this->xpath->query( '//link[ @rel = "preconnect" and @crossorigin and starts-with( @href, "https://fonts.gstatic.com" ) ]', $this->head )->length
-			);
-			if ( $needs_preconnect_link ) {
-				$link = AMP_DOM_Utils::create_node( $this->dom, 'link', array(
-					'rel'         => 'preconnect',
-					'href'        => 'https://fonts.gstatic.com/',
-					'crossorigin' => '',
-				) );
-				$this->head->insertBefore( $link ); // Note that \AMP_Theme_Support::ensure_required_markup() will put this in the optimal order.
-			}
-			return;
-		}
-
-		$css_file_path = $this->get_validated_url_file_path( $href, array( 'css', 'less', 'scss', 'sass' ) );
-
-		if ( is_wp_error( $css_file_path ) && ( 'disallowed_file_extension' === $css_file_path->get_error_code() || 'external_file_url' === $css_file_path->get_error_code() ) ) {
-			$contents = $this->fetch_external_stylesheet( $normalized_url );
-			if ( is_wp_error( $contents ) ) {
-				$this->remove_invalid_child( $element, array(
-					'code'    => $css_file_path->get_error_code(),
-					'message' => $css_file_path->get_error_message(),
-					'type'    => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
-				) );
-				return;
-			} else {
-				$stylesheet = $contents;
-			}
-		} elseif ( is_wp_error( $css_file_path ) ) {
-			$this->remove_invalid_child( $element, array(
-				'code'    => $css_file_path->get_error_code(),
-				'message' => $css_file_path->get_error_message(),
-				'type'    => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
-			) );
-			return;
-		} else {
-			$stylesheet = file_get_contents( $css_file_path ); // phpcs:ignore -- It's a local filesystem path not a remote request.
-		}
-
-		if ( false === $stylesheet ) {
-			$this->remove_invalid_child( $element, array(
-				'code' => 'stylesheet_file_missing',
-				'type' => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
-			) );
-			return;
-		}
-
-		// Honor the link's media attribute.
-		$media = $element->getAttribute( 'media' );
-		if ( $media && 'all' !== $media ) {
-			$stylesheet = sprintf( '@media %s { %s }', $media, $stylesheet );
-		}
-
-		$this->set_current_node( $element ); // And sources when needing to be located.
-
-		$processed = $this->process_stylesheet( $stylesheet, array(
-			'allowed_at_rules'   => $this->style_custom_cdata_spec['css_spec']['allowed_at_rules'],
-			'property_whitelist' => $this->style_custom_cdata_spec['css_spec']['declaration'],
-			'stylesheet_url'     => $href,
-			'stylesheet_path'    => $css_file_path,
-		) );
-
-		$this->pending_stylesheets[] = array_merge(
-			array(
-				'keyframes' => false,
-				'node'      => $element,
-				'sources'   => $this->current_sources, // Needed because node is removed below.
-			),
-			wp_array_slice_assoc( $processed, array( 'stylesheet', 'imported_font_urls' ) )
-		);
-
-		// Remove now that styles have been processed.
-		$element->parentNode->removeChild( $element );
-
-		$this->set_current_node( null );
-	}
-
-	/**
-	 * Fetch external stylesheet.
-	 *
-	 * @param string $url External stylesheet URL.
-	 * @return string|WP_Error Stylesheet contents or WP_Error.
-	 */
-	private function fetch_external_stylesheet( $url ) {
-		$cache_key = md5( $url );
-		$contents  = get_transient( $cache_key );
-		if ( false === $contents ) {
-			$r = wp_remote_get( $url );
-			if ( 200 !== wp_remote_retrieve_response_code( $r ) ) {
-				$contents = new WP_Error(
-					wp_remote_retrieve_response_code( $r ),
-					wp_remote_retrieve_response_message( $r )
-				);
-			} else {
-				$contents = wp_remote_retrieve_body( $r );
-			}
-			set_transient( $cache_key, $contents, MONTH_IN_SECONDS );
-		}
-		return $contents;
-	}
-
-	/**
-	 * Process stylesheet.
-	 *
-	 * Sanitized invalid CSS properties and rules, removes rules which do not
-	 * apply to the current document, and compresses the CSS to remove whitespace and comments.
-	 *
-	 * @since 1.0
-	 *
-	 * @param string $stylesheet Stylesheet.
-	 * @param array  $options {
-	 *     Options.
-	 *
-	 *     @type string[] $property_whitelist          Exclusively-allowed properties.
-	 *     @type string[] $property_blacklist          Disallowed properties.
-	 *     @type string   $stylesheet_url              Original URL for stylesheet when originating via link or @import.
-	 *     @type string   $stylesheet_path             Original filesystem path for stylesheet when originating via link or @import.
-	 *     @type array    $allowed_at_rules            Allowed @-rules.
-	 *     @type bool     $validate_keyframes          Whether keyframes should be validated.
-	 * }
-	 * @return array {
-	 *    Processed stylesheet.
-	 *
-	 *    @type array $stylesheet         Stylesheet parts, where arrays are tuples for declaration blocks.
-	 *    @type array $validation_results Validation results, array containing arrays with error and sanitized keys.
-	 *    @type array $imported_font_urls Imported font stylesheet URLs.
-	 * }
-	 */
-	private function process_stylesheet( $stylesheet, $options = array() ) {
-		$parsed      = null;
-		$cache_key   = null;
-		$cache_group = 'amp-parsed-stylesheet-v13'; // This should be bumped whenever the PHP-CSS-Parser is updated.
-
-		$cache_impacting_options = array_merge(
-			wp_array_slice_assoc(
-				$options,
-				array( 'property_whitelist', 'property_blacklist', 'stylesheet_url', 'allowed_at_rules' )
-			),
-			wp_array_slice_assoc(
-				$this->args,
-				array( 'should_locate_sources', 'parsed_cache_variant' )
-			),
-			array(
-				'language' => get_bloginfo( 'language' ), // Used to tree-shake html[lang] selectors.
-			)
-		);
-
-		$cache_key = md5( $stylesheet . wp_json_encode( $cache_impacting_options ) );
-
-		if ( wp_using_ext_object_cache() ) {
-			$parsed = wp_cache_get( $cache_key, $cache_group );
-		} else {
-			$parsed = get_transient( $cache_key . $cache_group );
-		}
-
-		/*
-		 * Make sure that the parsed stylesheet was cached with current sanitizations.
-		 * The should_sanitize_validation_error method prevents duplicates from being reported.
-		 */
-		if ( ! empty( $parsed['validation_results'] ) ) {
-			foreach ( $parsed['validation_results'] as $validation_result ) {
-				$sanitized = $this->should_sanitize_validation_error( $validation_result['error'] );
-				if ( $sanitized !== $validation_result['sanitized'] ) {
-					$parsed = null; // Change to sanitization of validation error detected, so cache cannot be used.
-					break;
-				}
-			}
-		}
-
-		if ( ! $parsed || ! isset( $parsed['stylesheet'] ) || ! is_array( $parsed['stylesheet'] ) ) {
-			$parsed = $this->prepare_stylesheet( $stylesheet, $options );
-
-			/*
-			 * When an object cache is not available, we cache with an expiration to prevent the options table from
-			 * getting filled infinitely. On the other hand, if an external object cache is available then we don't
-			 * set an expiration because it should implement LRU cache expulsion policy.
-			 */
-			if ( wp_using_ext_object_cache() ) {
-				wp_cache_set( $cache_key, $parsed, $cache_group );
-			} else {
-				// The expiration is to ensure transient doesn't stick around forever since no LRU flushing like with external object cache.
-				set_transient( $cache_key . $cache_group, $parsed, MONTH_IN_SECONDS );
-			}
-		}
-
-		return $parsed;
-	}
-
-	/**
-	 * Parse imported stylesheet.
-	 *
-	 * @param Import  $item     Import object.
-	 * @param CSSList $css_list CSS List.
-	 * @param array   $options {
-	 *     Options.
-	 *
-	 *     @type string $stylesheet_url Original URL for stylesheet when originating via link or @import.
-	 * }
-	 * @return array Validation results.
-	 */
-	private function parse_import_stylesheet( Import $item, CSSList $css_list, $options ) {
-		$results      = array();
-		$at_rule_args = $item->atRuleArgs();
-		$location     = array_shift( $at_rule_args );
-		$media_query  = array_shift( $at_rule_args );
-
-		if ( isset( $options['stylesheet_url'] ) ) {
-			$this->real_path_urls( array( $location ), $options['stylesheet_url'] );
-		}
-
-		$import_stylesheet_url = $location->getURL()->getString();
-
-		// Prevent importing something that has already been imported, and avoid infinite recursion.
-		if ( isset( $this->processed_imported_stylesheet_urls[ $import_stylesheet_url ] ) ) {
-			$css_list->remove( $item );
-			return array();
-		}
-		$this->processed_imported_stylesheet_urls[ $import_stylesheet_url ] = true;
-
-		// Prevent importing font stylesheets from allowed font CDNs. These will get added to the document as links instead.
-		$https_import_stylesheet_url = preg_replace( '#^(http:)?(?=//)#', 'https:', $import_stylesheet_url );
-		if ( $this->allowed_font_src_regex && preg_match( $this->allowed_font_src_regex, $https_import_stylesheet_url ) ) {
-			$this->imported_font_urls[] = $https_import_stylesheet_url;
-			$css_list->remove( $item );
-			_doing_it_wrong(
-				'wp_enqueue_style',
-				esc_html( sprintf(
-					/* translators: %s is URL to font CDN */
-					__( 'It is not a best practice to use @import to load font CDN stylesheets. Please use wp_enqueue_style() to enqueue %s as its own separate script.', 'amp' ),
-					$import_stylesheet_url
-				) ),
-				'1.0'
-			);
-			return array();
-		}
-
-		$css_file_path = $this->get_validated_url_file_path( $import_stylesheet_url, array( 'css', 'less', 'scss', 'sass' ) );
-
-		if ( is_wp_error( $css_file_path ) && ( 'disallowed_file_extension' === $css_file_path->get_error_code() || 'external_file_url' === $css_file_path->get_error_code() ) ) {
-			$contents = $this->fetch_external_stylesheet( $import_stylesheet_url );
-			if ( is_wp_error( $contents ) ) {
-				$error     = array(
-					'code'    => $contents->get_error_code(),
-					'message' => $contents->get_error_message(),
-					'type'    => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
-				);
-				$sanitized = $this->should_sanitize_validation_error( $error );
-				if ( $sanitized ) {
-					$css_list->remove( $item );
-				}
-				$results[] = compact( 'error', 'sanitized' );
-				return $results;
-			} else {
-				$stylesheet = $contents;
-			}
-		} elseif ( is_wp_error( $css_file_path ) ) {
-			$error     = array(
-				'code'    => $css_file_path->get_error_code(),
-				'message' => $css_file_path->get_error_message(),
-				'type'    => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
-			);
-			$sanitized = $this->should_sanitize_validation_error( $error );
-			if ( $sanitized ) {
-				$css_list->remove( $item );
-			}
-			$results[] = compact( 'error', 'sanitized' );
-			return $results;
-		} else {
-			$stylesheet = file_get_contents( $css_file_path ); // phpcs:ignore -- It's a local filesystem path not a remote request.
-		}
-
-		if ( $media_query ) {
-			$stylesheet = sprintf( '@media %s { %s }', $media_query, $stylesheet );
-		}
-
-		$options['stylesheet_url'] = $import_stylesheet_url;
-
-		$parsed_stylesheet = $this->parse_stylesheet( $stylesheet, $options );
-
-		$results = array_merge(
-			$results,
-			$parsed_stylesheet['validation_results']
-		);
-
-		/**
-		 * CSS Doc.
-		 *
-		 * @var Document $css_document
-		 */
-		$css_document = $parsed_stylesheet['css_document'];
-
-		if ( ! empty( $parsed_stylesheet['css_document'] ) ) {
-			$css_list->replace( $item, $css_document->getContents() );
-		} else {
-			$css_list->remove( $item );
-		}
-
-		return $results;
-	}
-
-	/**
-	 * Parse stylesheet.
-	 *
-	 * @since 1.0
-	 *
-	 * @param string $stylesheet_string Stylesheet.
-	 * @param array  $options           Options. See definition in \AMP_Style_Sanitizer::process_stylesheet().
-	 * @return array {
-	 *    Parsed stylesheet.
-	 *
-	 *    @type Document $css_document       CSS Document.
-	 *    @type array    $validation_results Validation results, array containing arrays with error and sanitized keys.
-	 * }
-	 */
-	private function parse_stylesheet( $stylesheet_string, $options ) {
-		$validation_results = array();
-		$css_document       = null;
-
-		$this->imported_font_urls = array();
-		try {
-			// Remove spaces from data URLs, which cause errors and PHP-CSS-Parser can't handle them.
-			$stylesheet_string = $this->remove_spaces_from_data_urls( $stylesheet_string );
-
-			$parser_settings = Sabberworm\CSS\Settings::create();
-			$css_parser      = new Sabberworm\CSS\Parser( $stylesheet_string, $parser_settings );
-			$css_document    = $css_parser->parse(); // @todo If 'utf-8' is not $css_parser->getCharset() then issue warning?
-
-			if ( ! empty( $options['stylesheet_url'] ) ) {
-				$this->real_path_urls(
-					array_filter(
-						$css_document->getAllValues(),
-						function ( $value ) {
-							return $value instanceof URL;
-						}
-					),
-					$options['stylesheet_url']
-				);
-			}
-
-			$validation_results = array_merge(
-				$validation_results,
-				$this->process_css_list( $css_document, $options )
-			);
-		} catch ( Exception $exception ) {
-			$error = array(
-				'code'    => 'css_parse_error',
-				'message' => $exception->getMessage(),
-				'type'    => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
-			);
-
-			/*
-			 * This is not a recoverable error, so sanitized here is just used to give user control
-			 * over whether to proceed with serving this exception-raising stylesheet in AMP.
-			 */
-			$sanitized = $this->should_sanitize_validation_error( $error );
-
-			$validation_results[] = compact( 'error', 'sanitized' );
-		}
-		return array_merge(
-			compact( 'validation_results', 'css_document' ),
-			array(
-				'imported_font_urls' => $this->imported_font_urls,
-			)
-		);
-	}
-
-	/**
-	 * Prepare stylesheet.
-	 *
-	 * @since 1.0
-	 *
-	 * @param string $stylesheet_string Stylesheet.
-	 * @param array  $options           Options. See definition in \AMP_Style_Sanitizer::process_stylesheet().
-	 * @return array {
-	 *    Prepared stylesheet.
-	 *
-	 *    @type array $stylesheet         Stylesheet parts, where arrays are tuples for declaration blocks.
-	 *    @type array $validation_results Validation results, array containing arrays with error and sanitized keys.
-	 *    @type array $imported_font_urls Imported font stylesheet URLs.
-	 * }
-	 */
-	private function prepare_stylesheet( $stylesheet_string, $options = array() ) {
-		$start_time = microtime( true );
-
-		$options = array_merge(
-			array(
-				'allowed_at_rules'   => array(),
-				'property_blacklist' => array(
-					// See <https://www.ampproject.org/docs/design/responsive/style_pages#disallowed-styles>.
-					'behavior',
-					'-moz-binding',
-				),
-				'property_whitelist' => array(),
-				'validate_keyframes' => false,
-				'stylesheet_url'     => null,
-				'stylesheet_path'    => null,
-			),
-			$options
-		);
-
-		// Strip the dreaded UTF-8 byte order mark (BOM, \uFEFF). This should ideally get handled by PHP-CSS-Parser <https://github.com/sabberworm/PHP-CSS-Parser/issues/150>.
-		$stylesheet_string = preg_replace( '/^\xEF\xBB\xBF/', '', $stylesheet_string );
-
-		$stylesheet         = array();
-		$parsed_stylesheet  = $this->parse_stylesheet( $stylesheet_string, $options );
-		$validation_results = $parsed_stylesheet['validation_results'];
-		if ( ! empty( $parsed_stylesheet['css_document'] ) ) {
-			$css_document = $parsed_stylesheet['css_document'];
-
-			$output_format = Sabberworm\CSS\OutputFormat::createCompact();
-			$output_format->setSemicolonAfterLastRule( false );
-
-			$before_declaration_block          = '/*AMP_WP_BEFORE_DECLARATION_BLOCK*/';
-			$between_selectors                 = '/*AMP_WP_BETWEEN_SELECTORS*/';
-			$after_declaration_block_selectors = '/*AMP_WP_BEFORE_DECLARATION_SELECTORS*/';
-			$after_declaration_block           = '/*AMP_WP_AFTER_DECLARATION*/';
-			$before_at_rule                    = '/*AMP_WP_BEFORE_AT_RULE*/';
-			$after_at_rule                     = '/*AMP_WP_AFTER_AT_RULE*/';
-
-			$output_format->set( 'BeforeDeclarationBlock', $before_declaration_block );
-			$output_format->set( 'SpaceBeforeSelectorSeparator', $between_selectors );
-			$output_format->set( 'AfterDeclarationBlockSelectors', $after_declaration_block_selectors );
-			$output_format->set( 'AfterDeclarationBlock', $after_declaration_block );
-			$output_format->set( 'BeforeAtRuleBlock', $before_at_rule );
-			$output_format->set( 'AfterAtRuleBlock', $after_at_rule );
-
-			$stylesheet_string = $css_document->render( $output_format );
-
-			$pattern  = '#';
-			$pattern .= preg_quote( $before_at_rule, '#' );
-			$pattern .= '|';
-			$pattern .= preg_quote( $after_at_rule, '#' );
-			$pattern .= '|';
-			$pattern .= '(' . preg_quote( $before_declaration_block, '#' ) . ')';
-			$pattern .= '(.+?)';
-			$pattern .= preg_quote( $after_declaration_block_selectors, '#' );
-			$pattern .= '(.+?)';
-			$pattern .= preg_quote( $after_declaration_block, '#' );
-			$pattern .= '#s';
-
-			$dynamic_selector_pattern = null;
-			if ( ! empty( $this->args['dynamic_element_selectors'] ) ) {
-				$dynamic_selector_pattern = implode( '|', array_map(
-					function( $selector ) {
-						return preg_quote( $selector, '#' );
-					},
-					$this->args['dynamic_element_selectors']
-				) );
-			}
-
-			$split_stylesheet = preg_split( $pattern, $stylesheet_string, -1, PREG_SPLIT_DELIM_CAPTURE );
-			$length           = count( $split_stylesheet );
-			for ( $i = 0; $i < $length; $i++ ) {
-				if ( $before_declaration_block === $split_stylesheet[ $i ] ) {
-
-					// Skip keyframe-selector, which is can be: from | to | <percentage>.
-					if ( preg_match( '/^((from|to)\b|-?\d+(\.\d+)?%)/i', $split_stylesheet[ $i + 1 ] ) ) {
-						$stylesheet[] = str_replace( $between_selectors, '', $split_stylesheet[ ++$i ] ) . $split_stylesheet[ ++$i ];
-						continue;
-					}
-
-					$selectors   = explode( $between_selectors . ',', $split_stylesheet[ ++$i ] );
-					$declaration = $split_stylesheet[ ++$i ];
-
-					$selectors_parsed = array();
-					foreach ( $selectors as $selector ) {
-						$selectors_parsed[ $selector ] = array();
-
-						// Remove :not() and pseudo selectors to eliminate false negatives, such as with `body:not(.title-tagline-hidden) .site-branding-text`.
-						$reduced_selector = preg_replace( '/:[a-zA-Z0-9_-]+(\(.+?\))?/', '', $selector );
-
-						// Remove attribute selectors to eliminate false negative, such as with `.social-navigation a[href*="example.com"]:before`.
-						$reduced_selector = preg_replace( '/\[\w.*?\]/', '', $reduced_selector );
-
-						// Ignore any selector terms that occur under a dynamic selector.
-						if ( $dynamic_selector_pattern ) {
-							$reduced_selector = preg_replace( '#((?:' . $dynamic_selector_pattern . ')(?:\.[a-z0-9_-]+)*)[^a-z0-9_-].*#si', '$1', $reduced_selector . ' ' );
-						}
-
-						$reduced_selector = preg_replace_callback(
-							'/\.([a-zA-Z0-9_-]+)/',
-							function( $matches ) use ( $selector, &$selectors_parsed ) {
-								$selectors_parsed[ $selector ]['classes'][] = $matches[1];
-								return '';
-							},
-							$reduced_selector
-						);
-						$reduced_selector = preg_replace_callback(
-							'/#([a-zA-Z0-9_-]+)/',
-							function( $matches ) use ( $selector, &$selectors_parsed ) {
-								$selectors_parsed[ $selector ]['ids'][] = $matches[1];
-								return '';
-							},
-							$reduced_selector
-						);
-
-						if ( preg_match_all( '/[a-zA-Z0-9_-]+/', $reduced_selector, $matches ) ) {
-							$selectors_parsed[ $selector ]['tags'] = $matches[0];
-						}
-					}
-
-					$stylesheet[] = array(
-						$selectors_parsed,
-						$declaration,
-					);
-				} else {
-					$stylesheet[] = $split_stylesheet[ $i ];
-				}
-			}
-		}
-
-		$this->parse_css_duration += ( microtime( true ) - $start_time );
-
-		return array_merge(
-			compact( 'stylesheet', 'validation_results' ),
-			array(
-				'imported_font_urls' => $parsed_stylesheet['imported_font_urls'],
-			)
-		);
-	}
-
-	/**
-	 * Previous return values from calls to should_sanitize_validation_error().
-	 *
-	 * This is used to prevent duplicates from being reported when the sanitization status
-	 * changes for a validation error in a previously-cached stylesheet.
-	 *
-	 * @see AMP_Style_Sanitizer::should_sanitize_validation_error()
-	 * @var array
-	 */
-	protected $previous_should_sanitize_validation_error_results = array();
-
-	/**
-	 * Check whether or not sanitization should occur in response to validation error.
-	 *
-	 * Supply sources to the error and the current node to data.
-	 *
-	 * @since 1.0
-	 *
-	 * @param array $validation_error Validation error.
-	 * @param array $data Data including the node.
-	 * @return bool Whether to sanitize.
-	 */
-	public function should_sanitize_validation_error( $validation_error, $data = array() ) {
-		if ( ! isset( $data['node'] ) ) {
-			$data['node'] = $this->current_node;
-		}
-		if ( ! isset( $validation_error['sources'] ) ) {
-			$validation_error['sources'] = $this->current_sources;
-		}
-
-		/*
-		 * This is used to prevent duplicates from being reported when the sanitization status
-		 * changes for a validation error in a previously-cached stylesheet.
-		 */
-		$args = compact( 'validation_error', 'data' );
-		foreach ( $this->previous_should_sanitize_validation_error_results as $result ) {
-			if ( $result['args'] === $args ) {
-				return $result['sanitized'];
-			}
-		}
-
-		$sanitized = parent::should_sanitize_validation_error( $validation_error, $data );
-
-		$this->previous_should_sanitize_validation_error_results[] = compact( 'args', 'sanitized' );
-		return $sanitized;
-	}
-
-	/**
-	 * Remove spaces from data URLs which PHP-CSS-Parser doesn't handle.
-	 *
-	 * @since 1.0
-	 *
-	 * @param string $css CSS.
-	 * @return string CSS with spaces removed from data URLs.
-	 */
-	private function remove_spaces_from_data_urls( $css ) {
-		return preg_replace_callback(
-			'/\burl\([^}]*?\)/',
-			function( $matches ) {
-				return preg_replace( '/\s+/', '', $matches[0] );
-			},
-			$css
-		);
-	}
-
-	/**
-	 * Process CSS list.
-	 *
-	 * @since 1.0
-	 *
-	 * @param CSSList $css_list CSS List.
-	 * @param array   $options Options.
-	 * @return array Validation errors.
-	 */
-	private function process_css_list( CSSList $css_list, $options ) {
-		$results = array();
-
-		foreach ( $css_list->getContents() as $css_item ) {
-			$sanitized = false;
-			if ( $css_item instanceof DeclarationBlock && empty( $options['validate_keyframes'] ) ) {
-				$results = array_merge(
-					$results,
-					$this->process_css_declaration_block( $css_item, $css_list, $options )
-				);
-			} elseif ( $css_item instanceof AtRuleBlockList ) {
-				if ( ! in_array( $css_item->atRuleName(), $options['allowed_at_rules'], true ) ) {
-					$error     = array(
-						'code'    => self::ILLEGAL_AT_RULE_ERROR_CODE,
-						'at_rule' => $css_item->atRuleName(),
-						'type'    => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
-					);
-					$sanitized = $this->should_sanitize_validation_error( $error );
-					$results[] = compact( 'error', 'sanitized' );
-				}
-				if ( ! $sanitized ) {
-					$results = array_merge(
-						$results,
-						$this->process_css_list( $css_item, $options )
-					);
-				}
-			} elseif ( $css_item instanceof Import ) {
-				$results = array_merge(
-					$results,
-					$this->parse_import_stylesheet( $css_item, $css_list, $options )
-				);
-			} elseif ( $css_item instanceof AtRuleSet ) {
-				if ( ! in_array( $css_item->atRuleName(), $options['allowed_at_rules'], true ) ) {
-					$error     = array(
-						'code'    => self::ILLEGAL_AT_RULE_ERROR_CODE,
-						'at_rule' => $css_item->atRuleName(),
-						'type'    => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
-					);
-					$sanitized = $this->should_sanitize_validation_error( $error );
-					$results[] = compact( 'error', 'sanitized' );
-				}
-
-				if ( ! $sanitized ) {
-					$results = array_merge(
-						$results,
-						$this->process_css_declaration_block( $css_item, $css_list, $options )
-					);
-				}
-			} elseif ( $css_item instanceof KeyFrame ) {
-				if ( ! in_array( 'keyframes', $options['allowed_at_rules'], true ) ) {
-					$error     = array(
-						'code'    => self::ILLEGAL_AT_RULE_ERROR_CODE,
-						'at_rule' => $css_item->atRuleName(),
-						'type'    => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
-					);
-					$sanitized = $this->should_sanitize_validation_error( $error );
-					$results[] = compact( 'error', 'sanitized' );
-				}
-
-				if ( ! $sanitized ) {
-					$results = array_merge(
-						$results,
-						$this->process_css_keyframes( $css_item, $options )
-					);
-				}
-			} elseif ( $css_item instanceof AtRule ) {
-				if ( 'charset' === $css_item->atRuleName() ) {
-					/*
-					 * The @charset at-rule is not allowed in style elements, so it is not allowed in AMP.
-					 * If the @charset is defined, then it really should have already been acknowledged
-					 * by PHP-CSS-Parser when the CSS was parsed in the first place, so at this point
-					 * it is irrelevant and can be removed.
-					 */
-					$sanitized = true;
-				} else {
-					$error     = array(
-						'code'    => self::ILLEGAL_AT_RULE_ERROR_CODE,
-						'at_rule' => $css_item->atRuleName(),
-						'type'    => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
-					);
-					$sanitized = $this->should_sanitize_validation_error( $error );
-					$results[] = compact( 'error', 'sanitized' );
-				}
-			} else {
-				$error     = array(
-					'code' => 'unrecognized_css',
-					'item' => get_class( $css_item ),
-					'type' => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
-				);
-				$sanitized = $this->should_sanitize_validation_error( $error );
-				$results[] = compact( 'error', 'sanitized' );
-			}
-
-			if ( $sanitized ) {
-				$css_list->remove( $css_item );
-			}
-		}
-		return $results;
-	}
-
-	/**
-	 * Convert URLs in to non-relative real-paths.
-	 *
-	 * @param URL[]  $urls           URLs.
-	 * @param string $stylesheet_url Stylesheet URL.
-	 */
-	private function real_path_urls( $urls, $stylesheet_url ) {
-		$base_url = preg_replace( ':[^/]+(\?.*)?(#.*)?$:', '', $stylesheet_url );
-		if ( empty( $base_url ) ) {
-			return;
-		}
-
-		foreach ( $urls as $url ) {
-			// URLs cannot have spaces in them, so strip them (especially when spaces get erroneously injected in data: URLs).
-			$url_string = $url->getURL()->getString();
-
-			// For data: URLs, all that is needed is to remove spaces so set and continue.
-			if ( 'data:' === substr( $url_string, 0, 5 ) ) {
-				continue;
-			}
-
-			// If the URL is already absolute, continue since there there is nothing left to do.
-			$parsed_url = wp_parse_url( $url_string );
-			if ( ! empty( $parsed_url['host'] ) || empty( $parsed_url['path'] ) || '/' === substr( $parsed_url['path'], 0, 1 ) ) {
-				continue;
-			}
-
-			$relative_url = preg_replace( '#^\./#', '', $url->getURL()->getString() );
-
-			// Resolve any relative parent directory paths.
-			$real_url = $base_url . $relative_url;
-			do {
-				$real_url = preg_replace( '#[^/]+/../#', '', $real_url, -1, $count );
-			} while ( 0 !== $count );
-
-			$url->getURL()->setString( $real_url );
-		}
-	}
-
-	/**
-	 * Process CSS rule set.
-	 *
-	 * @since 1.0
-	 * @link https://www.ampproject.org/docs/design/responsive/style_pages#disallowed-styles
-	 * @link https://www.ampproject.org/docs/design/responsive/style_pages#restricted-styles
-	 *
-	 * @param RuleSet $ruleset  Ruleset.
-	 * @param CSSList $css_list CSS List.
-	 * @param array   $options  Options.
-	 *
-	 * @return array Validation results.
-	 */
-	private function process_css_declaration_block( RuleSet $ruleset, CSSList $css_list, $options ) {
-		$results = array();
-
-		if ( $ruleset instanceof DeclarationBlock ) {
-			$this->ampify_ruleset_selectors( $ruleset );
-			if ( 0 === count( $ruleset->getSelectors() ) ) {
-				$css_list->remove( $ruleset );
-				return $results;
-			}
-		}
-
-		// Remove disallowed properties.
-		if ( ! empty( $options['property_whitelist'] ) ) {
-			$properties = $ruleset->getRules();
-			foreach ( $properties as $property ) {
-				$vendorless_property_name = preg_replace( '/^-\w+-/', '', $property->getRule() );
-				if ( ! in_array( $vendorless_property_name, $options['property_whitelist'], true ) ) {
-					$error     = array(
-						'code'           => 'illegal_css_property',
-						'property_name'  => $property->getRule(),
-						'property_value' => $property->getValue(),
-						'type'           => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
-					);
-					$sanitized = $this->should_sanitize_validation_error( $error );
-					if ( $sanitized ) {
-						$ruleset->removeRule( $property->getRule() );
-					}
-					$results[] = compact( 'error', 'sanitized' );
-				}
-			}
-		} else {
-			foreach ( $options['property_blacklist'] as $illegal_property_name ) {
-				$properties = $ruleset->getRules( $illegal_property_name );
-				foreach ( $properties as $property ) {
-					$error     = array(
-						'code'           => 'illegal_css_property',
-						'property_name'  => $property->getRule(),
-						'property_value' => (string) $property->getValue(),
-						'type'           => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
-					);
-					$sanitized = $this->should_sanitize_validation_error( $error );
-					if ( $sanitized ) {
-						$ruleset->removeRule( $property->getRule() );
-					}
-					$results[] = compact( 'error', 'sanitized' );
-				}
-			}
-		}
-
-		if ( $ruleset instanceof AtRuleSet && 'font-face' === $ruleset->atRuleName() ) {
-			$this->process_font_face_at_rule( $ruleset );
-		}
-
-		$results = array_merge(
-			$results,
-			$this->transform_important_qualifiers( $ruleset, $css_list )
-		);
-
-		// Remove the ruleset if it is now empty.
-		if ( 0 === count( $ruleset->getRules() ) ) {
-			$css_list->remove( $ruleset );
-		}
-		// @todo Delete rules with selectors for -amphtml- class and i-amphtml- tags.
-		return $results;
-	}
-
-	/**
-	 * Process @font-face by making src URLs non-relative and converting data: URLs into (assumed) file URLs.
-	 *
-	 * @since 1.0
-	 *
-	 * @param AtRuleSet $ruleset Ruleset for @font-face.
-	 */
-	private function process_font_face_at_rule( AtRuleSet $ruleset ) {
-		$src_properties = $ruleset->getRules( 'src' );
-		if ( empty( $src_properties ) ) {
-			return;
-		}
-
-		foreach ( $src_properties as $src_property ) {
-			$value = $src_property->getValue();
-			if ( ! ( $value instanceof RuleValueList ) ) {
-				continue;
-			}
-
-			/*
-			 * The CSS Parser parses a src such as:
-			 *
-			 *    url(data:application/font-woff;...) format('woff'),
-			 *    url('Genericons.ttf') format('truetype'),
-			 *    url('Genericons.svg#genericonsregular') format('svg')
-			 *
-			 * As a list of components consisting of:
-			 *
-			 *    URL,
-			 *    RuleValueList( CSSFunction, URL ),
-			 *    RuleValueList( CSSFunction, URL ),
-			 *    CSSFunction
-			 *
-			 * Clearly the components here are not logically grouped. So the first step is to fix the order.
-			 */
-			$sources = array();
-			foreach ( $value->getListComponents() as $component ) {
-				if ( $component instanceof RuleValueList ) {
-					$subcomponents = $component->getListComponents();
-					$subcomponent  = array_shift( $subcomponents );
-					if ( $subcomponent ) {
-						if ( empty( $sources ) ) {
-							$sources[] = array( $subcomponent );
-						} else {
-							$sources[ count( $sources ) - 1 ][] = $subcomponent;
-						}
-					}
-					foreach ( $subcomponents as $subcomponent ) {
-						$sources[] = array( $subcomponent );
-					}
-				} else {
-					if ( empty( $sources ) ) {
-						$sources[] = array( $component );
-					} else {
-						$sources[ count( $sources ) - 1 ][] = $component;
-					}
-				}
-			}
-
-			/**
-			 * Source URL lists.
-			 *
-			 * @var URL[] $source_file_urls
-			 * @var URL[] $source_data_urls
-			 */
-			$source_file_urls = array();
-			$source_data_urls = array();
-			foreach ( $sources as $i => $source ) {
-				if ( $source[0] instanceof URL ) {
-					if ( 'data:' === substr( $source[0]->getURL()->getString(), 0, 5 ) ) {
-						$source_data_urls[ $i ] = $source[0];
-					} else {
-						$source_file_urls[ $i ] = $source[0];
-					}
-				}
-			}
-
-			// Convert data: URLs into regular URLs, assuming there will be a file present (e.g. woff fonts in core themes).
-			if ( empty( $source_file_urls ) ) {
-				continue;
-			}
-			$source_file_url = current( $source_file_urls );
-			foreach ( $source_data_urls as $i => $data_url ) {
-				$mime_type = strtok( substr( $data_url->getURL()->getString(), 5 ), ';' );
-				if ( ! $mime_type ) {
-					continue;
-				}
-				$extension   = preg_replace( ':.+/(.+-)?:', '', $mime_type );
-				$guessed_url = preg_replace(
-					':(?<=\.)\w+(\?.*)?(#.*)?$:', // Match the file extension in the URL.
-					$extension,
-					$source_file_url->getURL()->getString(),
-					1,
-					$count
-				);
-				if ( 1 !== $count ) {
-					continue;
-				}
-
-				// Ensure font file exists.
-				$path = $this->get_validated_url_file_path( $guessed_url, array( 'woff', 'woff2', 'ttf', 'otf', 'svg' ) );
-				if ( is_wp_error( $path ) ) {
-					continue;
-				}
-
-				$data_url->getURL()->setString( $guessed_url );
-				break;
-			}
-		}
-	}
-
-	/**
-	 * Process CSS keyframes.
-	 *
-	 * @since 1.0
-	 * @link https://www.ampproject.org/docs/design/responsive/style_pages#restricted-styles.
-	 * @link https://github.com/ampproject/amphtml/blob/b685a0780a7f59313666225478b2b79b463bcd0b/validator/validator-main.protoascii#L1002-L1043
-	 * @todo Tree shaking could be extended to keyframes, to omit a keyframe if it is not referenced by any rule.
-	 *
-	 * @param KeyFrame $css_list Ruleset.
-	 * @param array    $options  Options.
-	 * @return array Validation results.
-	 */
-	private function process_css_keyframes( KeyFrame $css_list, $options ) {
-		$results = array();
-		if ( ! empty( $options['property_whitelist'] ) ) {
-			foreach ( $css_list->getContents() as $rules ) {
-				if ( ! ( $rules instanceof DeclarationBlock ) ) {
-					$error     = array(
-						'code' => 'unrecognized_css',
-						'item' => get_class( $rules ),
-						'type' => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
-					);
-					$sanitized = $this->should_sanitize_validation_error( $error );
-					if ( $sanitized ) {
-						$css_list->remove( $rules );
-					}
-					$results[] = compact( 'error', 'sanitized' );
-					continue;
-				}
-
-				$results = array_merge(
-					$results,
-					$this->transform_important_qualifiers( $rules, $css_list )
-				);
-
-				$properties = $rules->getRules();
-				foreach ( $properties as $property ) {
-					$vendorless_property_name = preg_replace( '/^-\w+-/', '', $property->getRule() );
-					if ( ! in_array( $vendorless_property_name, $options['property_whitelist'], true ) ) {
-						$error     = array(
-							'code'           => 'illegal_css_property',
-							'property_name'  => $property->getRule(),
-							'property_value' => (string) $property->getValue(),
-							'type'           => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
-						);
-						$sanitized = $this->should_sanitize_validation_error( $error );
-						if ( $sanitized ) {
-							$rules->removeRule( $property->getRule() );
-						}
-						$results[] = compact( 'error', 'sanitized' );
-					}
-				}
-			}
-		}
-		return $results;
-	}
-
-	/**
-	 * Replace !important qualifiers with more specific rules.
-	 *
-	 * @since 1.0
-	 * @see https://www.npmjs.com/package/replace-important
-	 * @see https://www.ampproject.org/docs/fundamentals/spec#important
-	 *
-	 * @param RuleSet|DeclarationBlock $ruleset  Rule set.
-	 * @param CSSList                  $css_list CSS List.
-	 * @return array Validation results.
-	 */
-	private function transform_important_qualifiers( RuleSet $ruleset, CSSList $css_list ) {
-		$results = array();
-
-		// An !important only makes sense for rulesets that have selectors.
-		$allow_transformation = (
-			$ruleset instanceof DeclarationBlock
-			&&
-			! ( $css_list instanceof KeyFrame )
-		);
-
-		$properties = $ruleset->getRules();
-		$importants = array();
-		foreach ( $properties as $property ) {
-			if ( $property->getIsImportant() ) {
-				if ( $allow_transformation ) {
-					$importants[] = $property;
-					$property->setIsImportant( false );
-					$ruleset->removeRule( $property->getRule() );
-				} else {
-					$error     = array(
-						'code' => 'illegal_css_important',
-						'type' => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
-					);
-					$sanitized = $this->should_sanitize_validation_error( $error );
-					if ( $sanitized ) {
-						$property->setIsImportant( false );
-					}
-					$results[] = compact( 'error', 'sanitized' );
-				}
-			}
-		}
-		if ( ! $allow_transformation || empty( $importants ) ) {
-			return $results;
-		}
-
-		$important_ruleset = clone $ruleset;
-		$important_ruleset->setSelectors( array_map(
-			/**
-			 * Modify selectors to be more specific to roughly match the effect of !important.
-			 *
-			 * @link https://github.com/ampproject/ampstart/blob/4c21d69afdd07b4c60cd190937bda09901955829/tools/replace-important/lib/index.js#L88-L109
-			 *
-			 * @param Selector $old_selector Original selector.
-			 * @return Selector The new more-specific selector.
-			 */
-			function( Selector $old_selector ) {
-				// Calculate the specificity multiplier for the placeholder.
-				$specificity_multiplier = AMP_Style_Sanitizer::INLINE_SPECIFICITY_MULTIPLIER + 1 + floor( $old_selector->getSpecificity() / 100 );
-				if ( $old_selector->getSpecificity() % 100 > 0 ) {
-					$specificity_multiplier++;
-				}
-				if ( $old_selector->getSpecificity() % 10 > 0 ) {
-					$specificity_multiplier++;
-				}
-				$selector_mod = str_repeat( ':not(#_)', $specificity_multiplier ); // Here "_" is just a short single-char ID.
-
-				$new_selector = $old_selector->getSelector();
-
-				// Amend the selector mod to the first element in selector if it is already the root; otherwise add new root ancestor.
-				if ( preg_match( '/^\s*(html|:root)\b/i', $new_selector, $matches ) ) {
-					$new_selector = substr( $new_selector, 0, strlen( $matches[0] ) ) . $selector_mod . substr( $new_selector, strlen( $matches[0] ) );
-				} else {
-					$new_selector = sprintf( ':root%s %s', $selector_mod, $new_selector );
-				}
-				return new Selector( $new_selector );
-			},
-			$ruleset->getSelectors()
-		) );
-		$important_ruleset->setRules( $importants );
-
-		$i = array_search( $ruleset, $css_list->getContents(), true );
-		if ( false !== $i ) {
-			$css_list->splice( $i + 1, 0, array( $important_ruleset ) );
-		} else {
-			$css_list->append( $important_ruleset );
-		}
-
-		return $results;
-	}
-
-	/**
-	 * Collect and store all CSS style attributes.
-	 *
-	 * Collects the CSS styles from within the HTML contained in this instance's DOMDocument.
-	 *
-	 * @see Retrieve array of styles using $this->get_styles() after calling this method.
-	 *
-	 * @since 0.4
-	 * @since 0.7 Modified to use element passed by XPath query.
-	 *
-	 * @note Uses recursion to traverse down the tree of DOMDocument nodes.
-	 *
-	 * @param DOMElement $element Node.
-	 */
-	private function collect_inline_styles( $element ) {
-		$style_attribute = $element->getAttributeNode( 'style' );
-		if ( ! $style_attribute || ! trim( $style_attribute->nodeValue ) ) {
-			return;
-		}
-
-		$class = 'amp-wp-' . substr( md5( $style_attribute->nodeValue ), 0, 7 );
-		$root  = ':root' . str_repeat( ':not(#_)', self::INLINE_SPECIFICITY_MULTIPLIER );
-		$rule  = sprintf( '%s .%s { %s }', $root, $class, $style_attribute->nodeValue );
-
-		$this->set_current_node( $element ); // And sources when needing to be located.
-
-		$processed = $this->process_stylesheet( $rule, array(
-			'allowed_at_rules'   => array(),
-			'property_whitelist' => $this->style_custom_cdata_spec['css_spec']['declaration'],
-		) );
-
-		$element->removeAttribute( 'style' );
-
-		if ( $processed['stylesheet'] ) {
-			$this->pending_stylesheets[] = array(
-				'stylesheet' => $processed['stylesheet'],
-				'node'       => $element,
-				'sources'    => $this->current_sources,
-			);
-
-			if ( $element->hasAttribute( 'class' ) ) {
-				$element->setAttribute( 'class', $element->getAttribute( 'class' ) . ' ' . $class );
-			} else {
-				$element->setAttribute( 'class', $class );
-			}
-		}
-
-		$this->set_current_node( null );
-	}
-
-	/**
-	 * Finalize stylesheets for style[amp-custom] and style[amp-keyframes] elements.
-	 *
-	 * Concatenate all pending stylesheets, remove unused rules if necessary, and add to style elements in doc.
-	 * Combine all amp-keyframe styles and add them to the end of the body.
-	 *
-	 * @since 1.0
-	 * @see https://www.ampproject.org/docs/fundamentals/spec#keyframes-stylesheet
-	 */
-	private function finalize_styles() {
-
-		$stylesheet_sets = array(
-			'custom'    => array(
-				'source_map_comment'  => "\n\n/*# sourceURL=amp-custom.css */",
-				'total_size'          => 0,
-				'cdata_spec'          => $this->style_custom_cdata_spec,
-				'pending_stylesheets' => array(),
-				'final_stylesheets'   => array(),
-				'remove_unused_rules' => $this->args['remove_unused_rules'],
-			),
-			'keyframes' => array(
-				'source_map_comment'  => "\n\n/*# sourceURL=amp-keyframes.css */",
-				'total_size'          => 0,
-				'cdata_spec'          => $this->style_keyframes_cdata_spec,
-				'pending_stylesheets' => array(),
-				'final_stylesheets'   => array(),
-				'remove_unused_rules' => 'never', // Not relevant.
-			),
-		);
-
-		$imported_font_urls = array();
-
-		/*
-		 * On Native AMP themes when there are new/rejected validation errors present, a parsed stylesheet may include
-		 * @import rules. These must be moved to the beginning to be honored.
-		 */
-		$imports = array();
-
-		// Divide pending stylesheet between custom and keyframes, and calculate size of each.
-		while ( ! empty( $this->pending_stylesheets ) ) {
-			$pending_stylesheet = array_shift( $this->pending_stylesheets );
-
-			$set_name = ! empty( $pending_stylesheet['keyframes'] ) ? 'keyframes' : 'custom';
-			$size     = 0;
-			foreach ( $pending_stylesheet['stylesheet'] as $i => $part ) {
-				if ( is_string( $part ) ) {
-					$size += strlen( $part );
-					if ( '@import' === substr( $part, 0, 7 ) ) {
-						$imports[] = $part;
-						unset( $pending_stylesheet['stylesheet'][ $i ] );
-					}
-				} elseif ( is_array( $part ) ) {
-					$size += strlen( implode( ',', array_keys( $part[0] ) ) ); // Selectors.
-					$size += strlen( $part[1] ); // Declaration block.
-				}
-			}
-			$stylesheet_sets[ $set_name ]['total_size']           += $size;
-			$stylesheet_sets[ $set_name ]['imports']               = $imports;
-			$stylesheet_sets[ $set_name ]['pending_stylesheets'][] = $pending_stylesheet;
-
-			if ( ! empty( $pending_stylesheet['imported_font_urls'] ) ) {
-				$imported_font_urls = array_merge( $imported_font_urls, $pending_stylesheet['imported_font_urls'] );
-			}
-		}
-
-		// Process the pending stylesheets.
-		foreach ( array_keys( $stylesheet_sets ) as $set_name ) {
-			$stylesheet_sets[ $set_name ] = $this->finalize_stylesheet_set( $stylesheet_sets[ $set_name ] );
-		}
-
-		$this->stylesheets = $stylesheet_sets['custom']['final_stylesheets'];
-
-		// If we're not working with the document element (e.g. for legacy post templates) then there is nothing left to do.
-		if ( empty( $this->args['use_document_element'] ) ) {
-			return;
-		}
-
-		// Add style[amp-custom] to document.
-		if ( ! empty( $stylesheet_sets['custom']['final_stylesheets'] ) ) {
-
-			// Ensure style[amp-custom] is present in the document.
-			if ( ! $this->amp_custom_style_element ) {
-				$this->amp_custom_style_element = $this->dom->createElement( 'style' );
-				$this->amp_custom_style_element->setAttribute( 'amp-custom', '' );
-				$this->head->appendChild( $this->amp_custom_style_element );
-			}
-
-			$css  = implode( '', $stylesheet_sets['custom']['imports'] ); // For native dirty AMP.
-			$css .= implode( '', $stylesheet_sets['custom']['final_stylesheets'] );
-			$css .= $stylesheet_sets['custom']['source_map_comment'];
-
-			/*
-			 * Let the style[amp-custom] be populated with the concatenated CSS.
-			 * !important: Updating the contents of this style element by setting textContent is not
-			 * reliable across PHP/libxml versions, so this is why the children are removed and the
-			 * text node is then explicitly added containing the CSS.
-			 */
-			while ( $this->amp_custom_style_element->firstChild ) {
-				$this->amp_custom_style_element->removeChild( $this->amp_custom_style_element->firstChild );
-			}
-			$this->amp_custom_style_element->appendChild( $this->dom->createTextNode( $css ) );
-
-			$included_size          = 0;
-			$included_original_size = 0;
-			$excluded_size          = 0;
-			$excluded_original_size = 0;
-			$included_sources       = array();
-			foreach ( $stylesheet_sets['custom']['pending_stylesheets'] as $i => $pending_stylesheet ) {
-				if ( ! ( $pending_stylesheet['node'] instanceof DOMElement ) ) {
-					continue;
-				}
-				$message = sprintf( '% 6d B', $pending_stylesheet['size'] );
-				if ( $pending_stylesheet['size'] && $pending_stylesheet['size'] !== $pending_stylesheet['original_size'] ) {
-					$message .= sprintf( ' (%d%%)', $pending_stylesheet['size'] / $pending_stylesheet['original_size'] * 100 );
-				}
-				$message .= ': ';
-				$message .= $pending_stylesheet['node']->nodeName;
-				if ( $pending_stylesheet['node']->getAttribute( 'id' ) ) {
-					$message .= '#' . $pending_stylesheet['node']->getAttribute( 'id' );
-				}
-				if ( $pending_stylesheet['node']->getAttribute( 'class' ) ) {
-					$message .= '.' . $pending_stylesheet['node']->getAttribute( 'class' );
-				}
-				foreach ( $pending_stylesheet['node']->attributes as $attribute ) {
-					if ( 'id' !== $attribute->nodeName || 'class' !== $attribute->nodeName ) {
-						$message .= sprintf( '[%s=%s]', $attribute->nodeName, $attribute->nodeValue );
-					}
-				}
-
-				if ( ! empty( $pending_stylesheet['included'] ) ) {
-					$included_sources[]      = $message;
-					$included_size          += $pending_stylesheet['size'];
-					$included_original_size += $pending_stylesheet['original_size'];
-				} else {
-					$excluded_sources[]      = $message;
-					$excluded_size          += $pending_stylesheet['size'];
-					$excluded_original_size += $pending_stylesheet['original_size'];
-				}
-			}
-			$comment = '';
-			if ( ! empty( $included_sources ) && $included_original_size > 0 ) {
-				$comment .= esc_html__( 'The style[amp-custom] element is populated with:', 'amp' ) . "\n" . implode( "\n", $included_sources ) . "\n";
-				$comment .= sprintf(
-					/* translators: %1$d is number of included bytes, %2$d is percentage of total CSS actually included after tree shaking, %3$d is total included size */
-					esc_html__( 'Total included size: %1$s bytes (%2$d%% of %3$s total after tree shaking)', 'amp' ),
-					number_format_i18n( $included_size ),
-					$included_size / $included_original_size * 100,
-					number_format_i18n( $included_original_size )
-				) . "\n";
-			}
-			if ( ! empty( $excluded_sources ) && $excluded_original_size > 0 ) {
-				if ( $comment ) {
-					$comment .= "\n";
-				}
-				$comment .= esc_html__( 'The following stylesheets are too large to be included in style[amp-custom]:', 'amp' ) . "\n" . implode( "\n", $excluded_sources ) . "\n";
-
-				$comment .= sprintf(
-					/* translators: %1$d is number of excluded bytes, %2$d is percentage of total CSS actually excluded even after tree shaking, %3$d is total excluded size */
-					esc_html__( 'Total excluded size: %1$s bytes (%2$d%% of %3$s total after tree shaking)', 'amp' ),
-					number_format_i18n( $excluded_size ),
-					$excluded_size / $excluded_original_size * 100,
-					number_format_i18n( $excluded_original_size )
-				) . "\n";
-
-				$total_size          = $included_size + $excluded_size;
-				$total_original_size = $included_original_size + $excluded_original_size;
-				if ( $total_size !== $total_original_size ) {
-					$comment .= "\n";
-					$comment .= sprintf(
-						/* translators: %1$d is total combined bytes, %2$d is percentage of CSS after tree shaking, %3$d is total before tree shaking */
-						esc_html__( 'Total combined size: %1$s bytes (%2$d%% of %3$s total after tree shaking)', 'amp' ),
-						number_format_i18n( $total_size ),
-						( $total_size / $total_original_size ) * 100,
-						number_format_i18n( $total_original_size )
-					) . "\n";
-				}
-			}
-
-			if ( $comment ) {
-				$this->amp_custom_style_element->parentNode->insertBefore(
-					$this->dom->createComment( "\n$comment" ),
-					$this->amp_custom_style_element
-				);
-			}
-		}
-
-		/*
-		 * Add font stylesheets from CDNs which were extracted from @import rules.
-		 * We can't add crossorigin=anonymous to these since such a CORS request would not be made in the non-AMP version,
-		 * and so if the service worker cached the opaque response on the non-AMP version then it wouldn't be usable in
-		 * the AMP version if it was requested with CORS.
-		 */
-		foreach ( array_unique( $imported_font_urls ) as $imported_font_url ) {
-			$link = $this->dom->createElement( 'link' );
-			$link->setAttribute( 'rel', 'stylesheet' );
-			$link->setAttribute( 'href', $imported_font_url );
-			$this->head->appendChild( $link );
-		}
-
-		// Add style[amp-keyframes] to document.
-		if ( ! empty( $stylesheet_sets['keyframes']['final_stylesheets'] ) ) {
-			$body = $this->dom->getElementsByTagName( 'body' )->item( 0 );
-			if ( ! $body ) {
-				$this->should_sanitize_validation_error( array(
-					'code' => 'missing_body_element',
-					'type' => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
-				) );
-			} else {
-				$css  = implode( '', $stylesheet_sets['keyframes']['final_stylesheets'] );
-				$css .= $stylesheet_sets['keyframes']['source_map_comment'];
-
-				$style_element = $this->dom->createElement( 'style' );
-				$style_element->setAttribute( 'amp-keyframes', '' );
-				$style_element->appendChild( $this->dom->createTextNode( $css ) );
-				$body->appendChild( $style_element );
-			}
-		}
-	}
-
-	/**
-	 * Convert CSS selectors and remove obsolete selector hacks for IE.
-	 *
-	 * @param DeclarationBlock $ruleset Ruleset.
-	 */
-	private function ampify_ruleset_selectors( $ruleset ) {
-		$selectors = array();
-		$changes   = 0;
-		$language  = get_bloginfo( 'language' );
-		foreach ( $ruleset->getSelectors() as $old_selector ) {
-			$selector = $old_selector->getSelector();
-
-			// Automatically tree-shake IE6/IE7 hacks for selectors with `* html` and `*+html`.
-			if ( preg_match( '/^\*\s*\+?\s*html/', $selector ) ) {
-				$changes++;
-				continue;
-			}
-
-			// Automatically remove selectors that are for another language (and thus are irrelevant). This is safe because amp-bind'ed [lang] is not allowed.
-			$is_other_language = (
-				preg_match( '/^html\[lang(?P<starts_with>\^?)=([\'"]?)(?P<lang>.+?)\2\]/', $selector, $matches )
-				&&
-				(
-					empty( $matches['starts_with'] )
-					?
-					$language !== $matches['lang']
-					:
-					substr( $language, 0, strlen( $matches['lang'] ) ) !== $matches['lang']
-				)
-			);
-			if ( $is_other_language ) {
-				$changes++;
-				continue;
-			}
-
-			// An element (type) either starts a selector or is preceded by combinator, comma, opening paren, or closing brace.
-			$before_type_selector_pattern = '(?<=^|\(|\s|>|\+|~|,|})';
-			$after_type_selector_pattern  = '(?=$|[^a-zA-Z0-9_-])';
-
-			$edited_selectors = array( $selector );
-			foreach ( $this->selector_mappings as $html_selector => $amp_selectors ) { // Note: The $selector_mappings array contains ~6 items.
-				$html_pattern = '/' . $before_type_selector_pattern . preg_quote( $html_selector, '/' ) . $after_type_selector_pattern . '/i';
-				foreach ( $edited_selectors as &$edited_selector ) { // Note: The $edited_selectors array contains only item in the normal case.
-					$original_selector = $edited_selector;
-					$amp_selector      = array_shift( $amp_selectors );
-					$amp_tag_pattern   = '/' . $before_type_selector_pattern . preg_quote( $amp_selector, '/' ) . $after_type_selector_pattern . '/i';
-					preg_match( $amp_tag_pattern, $edited_selector, $matches );
-					if ( ! empty( $matches ) && $amp_selector === $matches[0] ) {
-						continue;
-					}
-					$edited_selector = preg_replace( $html_pattern, $amp_selector, $edited_selector, -1, $count );
-					if ( ! $count ) {
-						continue;
-					}
-					$changes += $count;
-					while ( ! empty( $amp_selectors ) ) { // Note: This array contains only a couple items.
-						$amp_selector       = array_shift( $amp_selectors );
-						$edited_selectors[] = preg_replace( $html_pattern, $amp_selector, $original_selector, -1, $count );
-					}
-				}
-			}
-			$selectors = array_merge( $selectors, $edited_selectors );
-		}
-
-		if ( $changes > 0 ) {
-			$ruleset->setSelectors( $selectors );
-		}
-	}
-
-	/**
-	 * Finalize a stylesheet set (amp-custom or amp-keyframes).
-	 *
-	 * @since 1.0
-	 *
-	 * @param array $stylesheet_set Stylesheet set.
-	 * @return array Finalized stylesheet set.
-	 */
-	private function finalize_stylesheet_set( $stylesheet_set ) {
-		$max_bytes         = $stylesheet_set['cdata_spec']['max_bytes'] - strlen( $stylesheet_set['source_map_comment'] );
-		$is_too_much_css   = $stylesheet_set['total_size'] > $max_bytes;
-		$should_tree_shake = (
-			'always' === $stylesheet_set['remove_unused_rules'] || (
-				$is_too_much_css
-				&&
-				'sometimes' === $stylesheet_set['remove_unused_rules']
-			)
-		);
-
-		if ( $is_too_much_css && $should_tree_shake && empty( $this->args['accept_tree_shaking'] ) ) {
-			$should_tree_shake = $this->should_sanitize_validation_error( array(
-				'code' => self::TREE_SHAKING_ERROR_CODE,
-				'type' => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
-			) );
-		}
-
-		$stylesheet_set['processed_nodes'] = array();
-
-		$final_size = 0;
-		$dom        = $this->dom;
-		foreach ( $stylesheet_set['pending_stylesheets'] as &$pending_stylesheet ) {
-			$stylesheet_parts = array();
-			$original_size    = 0;
-			foreach ( $pending_stylesheet['stylesheet'] as $stylesheet_part ) {
-				if ( is_string( $stylesheet_part ) ) {
-					$stylesheet_parts[] = $stylesheet_part;
-					$original_size     += strlen( $stylesheet_part );
-					continue;
-				}
-
-				list( $selectors_parsed, $declaration_block ) = $stylesheet_part;
-				if ( $should_tree_shake ) {
-					$selectors = array();
-					foreach ( $selectors_parsed as $selector => $parsed_selector ) {
-						$should_include = (
-							(
-								// If all class names are used in the doc.
-								(
-									empty( $parsed_selector['classes'] )
-									||
-									0 === count( array_diff( $parsed_selector['classes'], $this->get_used_class_names() ) )
-								)
-								&&
-								// If all IDs are used in the doc.
-								(
-									empty( $parsed_selector['ids'] )
-									||
-									0 === count( array_filter( $parsed_selector['ids'], function( $id ) use ( $dom ) {
-										return ! $dom->getElementById( $id );
-									} ) )
-								)
-								&&
-								// If tag names are present in the doc.
-								(
-									empty( $parsed_selector['tags'] )
-									||
-									0 === count( array_diff( $parsed_selector['tags'], $this->get_used_tag_names() ) )
-								)
-							)
-						);
-						if ( $should_include ) {
-							$selectors[] = $selector;
-						}
-					}
-				} else {
-					$selectors = array_keys( $selectors_parsed );
-				}
-				$stylesheet_part = implode( ',', $selectors ) . $declaration_block;
-				$original_size  += strlen( $stylesheet_part );
-				if ( ! empty( $selectors ) ) {
-					$stylesheet_parts[] = $stylesheet_part;
-				}
-			}
-
-			// Strip empty at-rules after tree shaking.
-			$stylesheet_part_count = count( $stylesheet_parts );
-			for ( $i = 0; $i < $stylesheet_part_count; $i++ ) {
-				$stylesheet_part = $stylesheet_parts[ $i ];
-				if ( '@' !== substr( $stylesheet_part, 0, 1 ) ) {
-					continue;
-				}
-
-				// Delete empty at-rules.
-				if ( '{}' === substr( $stylesheet_part, -2 ) ) {
-					$stylesheet_part_count--;
-					array_splice( $stylesheet_parts, $i, 1 );
-					$i--;
-					continue;
-				}
-
-				// Delete at-rules that were emptied due to tree-shaking.
-				if ( '{' === substr( $stylesheet_part, -1 ) ) {
-					$open_braces = 1;
-					for ( $j = $i + 1; $j < $stylesheet_part_count; $j++ ) {
-						$stylesheet_part = $stylesheet_parts[ $j ];
-						$is_at_rule      = '@' === substr( $stylesheet_part, 0, 1 );
-						if ( empty( $stylesheet_part ) ) {
-							continue; // There was a shaken rule.
-						} elseif ( $is_at_rule && '{}' === substr( $stylesheet_part, -2 ) ) {
-							continue; // The rule opens is empty from the start.
-						} elseif ( $is_at_rule && '{' === substr( $stylesheet_part, -1 ) ) {
-							$open_braces++;
-						} elseif ( '}' === $stylesheet_part ) {
-							$open_braces--;
-						} else {
-							break;
-						}
-
-						// Splice out the parts that are empty.
-						if ( 0 === $open_braces ) {
-							array_splice( $stylesheet_parts, $i, $j - $i + 1 );
-							$stylesheet_part_count = count( $stylesheet_parts );
-							$i--;
-							continue 2;
-						}
-					}
-				}
-			}
-			$pending_stylesheet['original_size'] = $original_size;
-
-			$stylesheet = implode( '', $stylesheet_parts );
-			unset( $stylesheet_parts );
-			$sheet_size                 = strlen( $stylesheet );
-			$pending_stylesheet['size'] = $sheet_size;
-
-			// Skip considering stylesheet if an identical one has already been processed.
-			$hash = md5( $stylesheet );
-			if ( isset( $stylesheet_set['final_stylesheets'][ $hash ] ) ) {
-				$pending_stylesheet['included'] = true;
-				continue;
-			}
-
-			// Report validation error if size is now too big.
-			if ( $final_size + $sheet_size > $max_bytes ) {
-				$validation_error = array(
-					'code' => 'excessive_css',
-					'type' => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
-				);
-				if ( isset( $pending_stylesheet['sources'] ) ) {
-					$validation_error['sources'] = $pending_stylesheet['sources'];
-				}
-
-				if ( $this->should_sanitize_validation_error( $validation_error, wp_array_slice_assoc( $pending_stylesheet, array( 'node' ) ) ) ) {
-					$pending_stylesheet['included'] = false;
-					continue; // Skip to the next stylesheet.
-				}
-			}
-
-			$final_size += $sheet_size;
-
-			$pending_stylesheet['included']               = true;
-			$stylesheet_set['final_stylesheets'][ $hash ] = $stylesheet;
-		}
-
-		return $stylesheet_set;
-	}
-}
diff --git a/includes/sanitizers/class-amp-tag-and-attribute-sanitizer.php b/includes/sanitizers/class-amp-tag-and-attribute-sanitizer.php
deleted file mode 100644
index 0d97a209eca..00000000000
--- a/includes/sanitizers/class-amp-tag-and-attribute-sanitizer.php
+++ /dev/null
@@ -1,1874 +0,0 @@
-<?php
-/**
- * Class AMP_Tag_And_Attribute_Sanitizer
- *
- * @package AMP
- */
-
-/**
- * Strips the tags and attributes from the content that are not allowed by the AMP spec.
- *
- * Allowed tags array is generated from this protocol buffer:
- *
- *     https://github.com/ampproject/amphtml/blob/master/validator/validator-main.protoascii
- *     by the python script in amp-wp/bin/amp_wp_build.py. See the comment at the top
- *     of that file for instructions to generate class-amp-allowed-tags-generated.php.
- *
- * @todo Need to check the following items that are not yet checked by this sanitizer:
- *
- *     - `also_requires_attr` - if one attribute is present, this requires another.
- *     - `ChildTagSpec`       - Places restrictions on the number and type of child tags.
- *     - `if_value_regex`     - if one attribute value matches, this places a restriction
- *                              on another attribute/value.
- *     - `mandatory_oneof`    - Within the context of the tag, exactly one of the attributes
- *                              must be present.
- */
-class AMP_Tag_And_Attribute_Sanitizer extends AMP_Base_Sanitizer {
-
-	/**
-	 * Allowed tags.
-	 *
-	 * @since 0.5
-	 *
-	 * @var string[]
-	 */
-	protected $allowed_tags;
-
-	/**
-	 * Globally-allowed attributes.
-	 *
-	 * @since 0.5
-	 *
-	 * @var array[][]
-	 */
-	protected $globally_allowed_attributes;
-
-	/**
-	 * Layout-allowed attributes.
-	 *
-	 * @since 0.5
-	 *
-	 * @var string[]
-	 */
-	protected $layout_allowed_attributes;
-
-	/**
-	 * Mapping of alternative names back to their primary names.
-	 *
-	 * @since 0.7
-	 * @var array
-	 */
-	protected $rev_alternate_attr_name_lookup = array();
-
-	/**
-	 * Stack.
-	 *
-	 * @since 0.5
-	 *
-	 * @var DOMElement[]
-	 */
-	private $stack = array();
-
-	/**
-	 * Default args.
-	 *
-	 * @since 0.5
-	 *
-	 * @var array
-	 */
-	protected $DEFAULT_ARGS = array();
-
-	/**
-	 * AMP script components that are discovered being required through sanitization.
-	 *
-	 * @var string[]
-	 */
-	protected $script_components = array();
-
-	/**
-	 * Keep track of nodes that should not be replaced to prevent duplicated validation errors since sanitization is rejected.
-	 *
-	 * @var array
-	 */
-	protected $should_not_replace_nodes = array();
-
-	/**
-	 * AMP_Tag_And_Attribute_Sanitizer constructor.
-	 *
-	 * @since 0.5
-	 *
-	 * @param DOMDocument $dom  DOM.
-	 * @param array       $args Args.
-	 */
-	public function __construct( $dom, $args = array() ) {
-		$this->DEFAULT_ARGS = array(
-			'amp_allowed_tags'                => AMP_Allowed_Tags_Generated::get_allowed_tags(),
-			'amp_globally_allowed_attributes' => AMP_Allowed_Tags_Generated::get_allowed_attributes(),
-			'amp_layout_allowed_attributes'   => AMP_Allowed_Tags_Generated::get_layout_attributes(),
-			'amp_bind_placeholder_prefix'     => AMP_DOM_Utils::get_amp_bind_placeholder_prefix(),
-		);
-
-		parent::__construct( $dom, $args );
-
-		if ( ! empty( $this->args['allow_dirty_styles'] ) ) {
-
-			// Allow style attribute on all elements.
-			$this->args['amp_globally_allowed_attributes']['style'] = array();
-
-			// Allow style elements.
-			$this->args['amp_allowed_tags']['style'][] = array(
-				'attr_spec_list' => array(
-					'type' => array(
-						'value_casei' => 'text/css',
-					),
-				),
-				'cdata'          => array(),
-				'tag_spec'       => array(
-					'spec_name' => 'style for Customizer preview',
-				),
-			);
-
-			// Allow stylesheet links.
-			$this->args['amp_allowed_tags']['link'][] = array(
-				'attr_spec_list' => array(
-					'async'       => array(),
-					'crossorigin' => array(),
-					'href'        => array(
-						'mandatory' => true,
-					),
-					'integrity'   => array(),
-					'media'       => array(),
-					'rel'         => array(
-						'dispatch_key' => 2,
-						'mandatory'    => true,
-						'value_casei'  => 'stylesheet',
-					),
-					'type'        => array(
-						'value_casei' => 'text/css',
-					),
-				),
-				'tag_spec'       => array(
-					'spec_name' => 'link rel=stylesheet for Customizer preview', // phpcs:ignore WordPress.WP.EnqueuedResources.NonEnqueuedStylesheet
-				),
-			);
-		}
-
-		// Allow scripts if requested.
-		if ( ! empty( $this->args['allow_dirty_scripts'] ) ) {
-			$this->args['amp_allowed_tags']['script'][] = array(
-				'attr_spec_list' => array(
-					'type'  => array(),
-					'src'   => array(),
-					'async' => array(),
-					'defer' => array(),
-				),
-				'cdata'          => array(),
-				'tag_spec'       => array(
-					'spec_name' => 'scripts for Customizer preview',
-				),
-			);
-		}
-
-		// Prepare whitelists.
-		$this->allowed_tags = $this->args['amp_allowed_tags'];
-		foreach ( AMP_Rule_Spec::$additional_allowed_tags as $tag_name => $tag_rule_spec ) {
-			$this->allowed_tags[ $tag_name ][] = $tag_rule_spec;
-		}
-
-		// @todo Do the same for body when !use_document_element?
-		if ( ! empty( $this->args['use_document_element'] ) ) {
-			foreach ( $this->allowed_tags['html'] as &$rule_spec ) {
-				unset( $rule_spec[ AMP_Rule_Spec::TAG_SPEC ][ AMP_Rule_Spec::MANDATORY_PARENT ] );
-			}
-		}
-
-		foreach ( $this->allowed_tags as &$tag_specs ) {
-			foreach ( $tag_specs as &$tag_spec ) {
-				if ( isset( $tag_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ] ) ) {
-					$tag_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ] = $this->process_alternate_names( $tag_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ] );
-				}
-			}
-		}
-		$this->globally_allowed_attributes = $this->process_alternate_names( $this->args['amp_globally_allowed_attributes'] );
-		$this->layout_allowed_attributes   = $this->process_alternate_names( $this->args['amp_layout_allowed_attributes'] );
-	}
-
-	/**
-	 * Return array of values that would be valid as an HTML `script` element.
-	 *
-	 * Array keys are AMP element names and array values are their respective
-	 * Javascript URLs from https://cdn.ampproject.org
-	 *
-	 * @since 0.7
-	 * @see amp_register_default_scripts()
-	 *
-	 * @return array() Returns component name as array key and true as value (or JavaScript URL string),
-	 *                  respectively. When true then the default component script URL will be used.
-	 *                  Will return an empty array if sanitization has yet to be run
-	 *                  or if it did not find any HTML elements to convert to AMP equivalents.
-	 */
-	public function get_scripts() {
-		return array_fill_keys( array_unique( $this->script_components ), true );
-	}
-
-	/**
-	 * Process alternative names in attribute spec list.
-	 *
-	 * @since 0.7
-	 *
-	 * @param array $attr_spec_list Attribute spec list.
-	 * @return array Modified attribute spec list.
-	 */
-	private function process_alternate_names( $attr_spec_list ) {
-		foreach ( $attr_spec_list as $attr_name => &$attr_spec ) {
-			if ( '[' === $attr_name[0] ) {
-				$placeholder_attr_name = $this->args['amp_bind_placeholder_prefix'] . trim( $attr_name, '[]' );
-				if ( ! isset( $attr_spec[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] ) ) {
-					$attr_spec[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] = array();
-				}
-				$attr_spec[ AMP_Rule_Spec::ALTERNATIVE_NAMES ][] = $placeholder_attr_name;
-			}
-
-			// Save all alternative names in lookup to improve performance.
-			if ( isset( $attr_spec[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] ) ) {
-				foreach ( $attr_spec[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] as $alternative_name ) {
-					$this->rev_alternate_attr_name_lookup[ $alternative_name ] = $attr_name;
-				}
-			}
-		}
-		return $attr_spec_list;
-	}
-
-	/**
-	 * Sanitize the elements from the HTML contained in this instance's DOMDocument.
-	 *
-	 * @since 0.5
-	 */
-	public function sanitize() {
-
-		// Add root of content to the stack.
-		$this->stack[] = $this->root_element;
-
-		/**
-		 * This loop traverses through the DOM tree iteratively.
-		 */
-		while ( ! empty( $this->stack ) ) {
-
-			// Get the next node to process.
-			$node = array_shift( $this->stack );
-
-			/**
-			 * Process this node.
-			 */
-			$this->process_node( $node );
-
-			/*
-			 * Push child nodes onto the stack, if any exist.
-			 * if node was removed, then it's parentNode value is null.
-			 */
-			if ( $node->parentNode ) {
-				$child = $node->firstChild;
-				while ( $child ) {
-					$this->stack[] = $child;
-					$child         = $child->nextSibling;
-				}
-			}
-		}
-	}
-
-	/**
-	 * Augment rule spec for validation.
-	 *
-	 * @since 1.0
-	 *
-	 * @param DOMElement $node      Node.
-	 * @param array      $rule_spec Rule spec.
-	 * @return array Augmented rule spec.
-	 */
-	private function get_rule_spec_list_to_validate( $node, $rule_spec ) {
-
-		// Expand extension_spec into a set of attr_spec_list.
-		if ( isset( $rule_spec[ AMP_Rule_Spec::TAG_SPEC ]['extension_spec'] ) ) {
-			$extension_spec = $rule_spec[ AMP_Rule_Spec::TAG_SPEC ]['extension_spec'];
-			$custom_attr    = 'amp-mustache' === $extension_spec['name'] ? 'custom-template' : 'custom-element';
-
-			$rule_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ][ $custom_attr ] = array(
-				AMP_Rule_Spec::VALUE     => $extension_spec['name'],
-				AMP_Rule_Spec::MANDATORY => true,
-			);
-
-			$versions = array_unique( array_merge(
-				isset( $extension_spec['allowed_versions'] ) ? $extension_spec['allowed_versions'] : array(),
-				isset( $extension_spec['version'] ) ? $extension_spec['version'] : array()
-			) );
-
-			$rule_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ]['src'] = array(
-				AMP_Rule_Spec::VALUE_REGEX => implode( '', array(
-					'^',
-					preg_quote( 'https://cdn.ampproject.org/v0/' . $extension_spec['name'] . '-' ),
-					'(' . implode( '|', $versions ) . ')',
-					'\.js$',
-				) ),
-			);
-		}
-
-		// Augment the attribute list according to the parent's reference points, if it has them.
-		if ( ! empty( $node->parentNode ) && isset( $this->allowed_tags[ $node->parentNode->nodeName ] ) ) {
-			foreach ( $this->allowed_tags[ $node->parentNode->nodeName ] as $parent_rule_spec ) {
-				if ( empty( $parent_rule_spec[ AMP_Rule_Spec::TAG_SPEC ]['reference_points'] ) ) {
-					continue;
-				}
-				foreach ( $parent_rule_spec[ AMP_Rule_Spec::TAG_SPEC ]['reference_points'] as $reference_point_spec_name => $reference_point_spec_instance_attrs ) {
-					$reference_point = AMP_Allowed_Tags_Generated::get_reference_point_spec( $reference_point_spec_name );
-					if ( empty( $reference_point[ AMP_Rule_Spec::ATTR_SPEC_LIST ] ) ) {
-						/*
-						 * See special case for amp-selector in AMP_Tag_And_Attribute_Sanitizer::is_amp_allowed_attribute()
-						 * where its reference point applies to any descendant elements, not just direct children.
-						 */
-						continue;
-					}
-					foreach ( $reference_point[ AMP_Rule_Spec::ATTR_SPEC_LIST ] as $attr_name => $reference_point_spec_attr ) {
-						$reference_point_spec_attr = array_merge(
-							$reference_point_spec_attr,
-							$reference_point_spec_instance_attrs
-						);
-
-						/*
-						 * Ignore mandatory constraint for now since this would end up causing other sibling children
-						 * getting removed due to missing a mandatory attribute. To sanitize this it would require
-						 * higher-level processing to look at an element's surrounding context, similar to how the
-						 * sanitizer does not yet handle the mandatory_oneof constraint.
-						 */
-						unset( $reference_point_spec_attr['mandatory'] );
-
-						$rule_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ][ $attr_name ] = $reference_point_spec_attr;
-					}
-				}
-			}
-		}
-		return $rule_spec;
-	}
-
-	/**
-	 * Process a node by checking if an element and its attributes are valid, and removing them when invalid.
-	 *
-	 * Attributes which are not valid are removed. Elements which are not allowed are also removed,
-	 * including elements which miss mandatory attributes.
-	 *
-	 * @param DOMNode $node Node.
-	 */
-	private function process_node( $node ) {
-
-		// Don't process text or comment nodes.
-		if ( XML_TEXT_NODE === $node->nodeType || XML_COMMENT_NODE === $node->nodeType || XML_CDATA_SECTION_NODE === $node->nodeType ) {
-			return;
-		}
-
-		// Remove nodes with tags that have not been whitelisted.
-		if ( ! $this->is_amp_allowed_tag( $node ) ) {
-
-			// If it's not an allowed tag, replace the node with it's children.
-			$this->replace_node_with_children( $node );
-
-			// Return early since this node no longer exists.
-			return;
-		}
-
-		/**
-		 * Node is now an element.
-		 *
-		 * @var DOMElement $node
-		 */
-
-		/*
-		 * Compile a list of rule_specs to validate for this node
-		 * based on tag name of the node.
-		 */
-		$rule_spec_list_to_validate = array();
-		$rule_spec_list             = array();
-		if ( isset( $this->allowed_tags[ $node->nodeName ] ) ) {
-			$rule_spec_list = $this->allowed_tags[ $node->nodeName ];
-		}
-		foreach ( $rule_spec_list as $id => $rule_spec ) {
-			if ( $this->validate_tag_spec_for_node( $node, $rule_spec[ AMP_Rule_Spec::TAG_SPEC ] ) ) {
-				$rule_spec_list_to_validate[ $id ] = $this->get_rule_spec_list_to_validate( $node, $rule_spec );
-			}
-		}
-
-		// If no valid rule_specs exist, then remove this node and return.
-		if ( empty( $rule_spec_list_to_validate ) ) {
-			$this->remove_node( $node );
-			return;
-		}
-
-		// The remaining validations all have to do with attributes.
-		$attr_spec_list = array();
-		$tag_spec       = array();
-		$cdata          = array();
-
-		/*
-		 * If we have exactly one rule_spec, use it's attr_spec_list
-		 * to validate the node's attributes.
-		 */
-		if ( 1 === count( $rule_spec_list_to_validate ) ) {
-			$rule_spec      = array_pop( $rule_spec_list_to_validate );
-			$attr_spec_list = $rule_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ];
-			$tag_spec       = $rule_spec[ AMP_Rule_Spec::TAG_SPEC ];
-			if ( isset( $rule_spec[ AMP_Rule_Spec::CDATA ] ) ) {
-				$cdata = $rule_spec[ AMP_Rule_Spec::CDATA ];
-			}
-		} else {
-			/*
-			 * If there is more than one valid rule_spec for this node,
-			 * then try to deduce which one is intended by inspecting
-			 * the node's attributes.
-			 */
-
-			/*
-			 * Get a score from each attr_spec_list by seeing how many
-			 * attributes and values match the node.
-			 */
-			$attr_spec_scores = array();
-			foreach ( $rule_spec_list_to_validate as $spec_id => $rule_spec ) {
-				$attr_spec_scores[ $spec_id ] = $this->validate_attr_spec_list_for_node( $node, $rule_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ] );
-			}
-
-			// Remove all spec lists that didn't match.
-			$attr_spec_scores = array_filter( $attr_spec_scores );
-
-			// If no attribute spec lists match, then the element must be removed.
-			if ( empty( $attr_spec_scores ) ) {
-				$this->remove_node( $node );
-				return;
-			}
-
-			// Get the key(s) to the highest score(s).
-			$spec_ids_sorted = array_keys( $attr_spec_scores, max( $attr_spec_scores ), true );
-
-			// If there is exactly one attr_spec with a max score, use that one.
-			if ( 1 === count( $spec_ids_sorted ) ) {
-				$attr_spec_list = $rule_spec_list_to_validate[ $spec_ids_sorted[0] ][ AMP_Rule_Spec::ATTR_SPEC_LIST ];
-				$tag_spec       = $rule_spec_list_to_validate[ $spec_ids_sorted[0] ][ AMP_Rule_Spec::TAG_SPEC ];
-				if ( isset( $rule_spec_list_to_validate[ $spec_ids_sorted[0] ][ AMP_Rule_Spec::CDATA ] ) ) {
-					$cdata = $rule_spec_list_to_validate[ $spec_ids_sorted[0] ][ AMP_Rule_Spec::CDATA ];
-				}
-			} else {
-				// This should not happen very often, but...
-				// If we're here, then we're not sure which spec should
-				// be used. Let's use the top scoring ones.
-				foreach ( $spec_ids_sorted as $id ) {
-					$spec_list = isset( $rule_spec_list_to_validate[ $id ][ AMP_Rule_Spec::ATTR_SPEC_LIST ] ) ? $rule_spec_list_to_validate[ $id ][ AMP_Rule_Spec::ATTR_SPEC_LIST ] : null;
-					if ( ! $this->is_missing_mandatory_attribute( $spec_list, $node ) ) {
-						$attr_spec_list = array_merge( $attr_spec_list, $spec_list );
-						$tag_spec       = array_merge(
-							$tag_spec,
-							$rule_spec_list_to_validate[ $id ][ AMP_Rule_Spec::TAG_SPEC ]
-						);
-						if ( isset( $rule_spec_list_to_validate[ $id ][ AMP_Rule_Spec::CDATA ] ) ) {
-							$cdata = array_merge( $cdata, $rule_spec_list_to_validate[ $id ][ AMP_Rule_Spec::CDATA ] );
-						}
-					}
-				}
-				$first_spec = reset( $rule_spec_list_to_validate );
-				if ( empty( $attr_spec_list ) && isset( $first_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ] ) ) {
-					$attr_spec_list = $first_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ];
-				}
-			}
-		}
-
-		if ( ! empty( $attr_spec_list ) && $this->is_missing_mandatory_attribute( $attr_spec_list, $node ) ) {
-			$this->remove_node( $node );
-			return;
-		}
-
-		// Remove element if it has illegal CDATA.
-		if ( ! empty( $cdata ) && $node instanceof DOMElement ) {
-			$validity = $this->validate_cdata_for_node( $node, $cdata );
-			if ( is_wp_error( $validity ) ) {
-				$this->remove_node( $node );
-				return;
-			}
-		}
-
-		$merged_attr_spec_list = array_merge(
-			$this->globally_allowed_attributes,
-			$attr_spec_list
-		);
-
-		// Amend spec list with layout.
-		if ( isset( $tag_spec['amp_layout'] ) ) {
-			$merged_attr_spec_list = array_merge( $merged_attr_spec_list, $this->layout_allowed_attributes );
-
-			if ( isset( $tag_spec['amp_layout']['supported_layouts'] ) ) {
-				$layouts = wp_array_slice_assoc( AMP_Rule_Spec::$layout_enum, $tag_spec['amp_layout']['supported_layouts'] );
-
-				$merged_attr_spec_list['layout'][ AMP_Rule_Spec::VALUE_REGEX_CASEI ] = '(' . implode( '|', $layouts ) . ')';
-			}
-		}
-
-		// Identify any remaining disallowed attributes.
-		$disallowed_attributes = $this->get_disallowed_attributes_in_node( $node, $merged_attr_spec_list );
-
-		// Identify attribute values that don't conform to the attr_spec.
-		$disallowed_attributes = $this->sanitize_disallowed_attribute_values_in_node( $node, $merged_attr_spec_list, $disallowed_attributes );
-
-		// If $disallowed_attributes is false then the entire element should be removed.
-		if ( false === $disallowed_attributes ) {
-			$this->remove_node( $node );
-			return;
-		}
-
-		// Remove all invalid attributes.
-		if ( ! empty( $disallowed_attributes ) ) {
-			/*
-			 * Capture all element attributes up front so that differing validation errors result when
-			 * one invalid attribute is accepted but the others are still rejected.
-			 */
-			$validation_error = array(
-				'element_attributes' => array(),
-			);
-			foreach ( $node->attributes as $attribute ) {
-				$validation_error['element_attributes'][ $attribute->nodeName ] = $attribute->nodeValue;
-			}
-			foreach ( $disallowed_attributes as $disallowed_attribute ) {
-				$this->remove_invalid_attribute( $node, $disallowed_attribute, $validation_error );
-			}
-		}
-
-		// Add required AMP component scripts if the element is still in the document.
-		if ( $node->parentNode ) {
-			if ( ! empty( $tag_spec['also_requires_tag_warning'] ) ) {
-				$this->script_components[] = strtok( $tag_spec['also_requires_tag_warning'][0], ' ' );
-			}
-			if ( ! empty( $tag_spec['requires_extension'] ) ) {
-				$this->script_components = array_merge( $this->script_components, $tag_spec['requires_extension'] );
-			}
-
-			// Check if element needs amp-bind component.
-			if ( $node instanceof DOMElement && ! in_array( 'amp-bind', $this->script_components, true ) ) {
-				foreach ( $node->attributes as $name => $value ) {
-					$is_bind_attribute = (
-						'[' === $name[0]
-						||
-						( isset( $this->rev_alternate_attr_name_lookup[ $name ] ) && '[' === $this->rev_alternate_attr_name_lookup[ $name ][0] )
-					);
-					if ( $is_bind_attribute ) {
-						$this->script_components[] = 'amp-bind';
-						break;
-					}
-				}
-			}
-		}
-	}
-
-	/**
-	 * Whether a node is missing a mandatory attribute.
-	 *
-	 * @param array      $attr_spec The attribute specification.
-	 * @param DOMElement $node      The DOMElement of the node to check.
-	 * @return boolean $is_missing boolean Whether a required attribute is missing.
-	 */
-	public function is_missing_mandatory_attribute( $attr_spec, $node ) {
-		if ( ! is_array( $attr_spec ) ) {
-			return false;
-		}
-		foreach ( $attr_spec as $attr_name => $attr_spec_rule_value ) {
-			if ( '\u' === substr( $attr_name, 0, 2 ) ) {
-				$attr_name = html_entity_decode( '&#x' . substr( $attr_name, 2 ) . ';' ); // Probably ⚡.
-			}
-			$is_mandatory     = isset( $attr_spec_rule_value[ AMP_Rule_Spec::MANDATORY ] ) ? ( true === $attr_spec_rule_value[ AMP_Rule_Spec::MANDATORY ] ) : false;
-			$attribute_exists = false;
-			if ( method_exists( $node, 'hasAttribute' ) ) {
-				$attribute_exists = $node->hasAttribute( $attr_name );
-				if ( ! $attribute_exists && ! empty( $attr_spec_rule_value[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] ) ) {
-					foreach ( $attr_spec_rule_value[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] as $alternative_attr_name ) {
-						if ( $node->hasAttribute( $alternative_attr_name ) ) {
-							$attribute_exists = true;
-							break;
-						}
-					}
-				}
-			}
-			if ( $is_mandatory && ! $attribute_exists ) {
-				return true;
-			}
-		}
-		return false;
-	}
-
-	/**
-	 * Validate element for its CDATA.
-	 *
-	 * @since 0.7
-	 *
-	 * @param DOMElement $element    Element.
-	 * @param array      $cdata_spec CDATA.
-	 * @return true|WP_Error True when valid or error when invalid.
-	 */
-	private function validate_cdata_for_node( $element, $cdata_spec ) {
-		if ( isset( $cdata_spec['blacklisted_cdata_regex'] ) ) {
-			if ( preg_match( '@' . $cdata_spec['blacklisted_cdata_regex']['regex'] . '@u', $element->textContent ) ) {
-				return new WP_Error( $cdata_spec['blacklisted_cdata_regex']['error_message'] );
-			}
-		} elseif ( isset( $cdata_spec['cdata_regex'] ) ) {
-			$delimiter = false === strpos( $cdata_spec['cdata_regex'], '@' ) ? '@' : '#';
-			if ( ! preg_match( $delimiter . $cdata_spec['cdata_regex'] . $delimiter . 'u', $element->textContent ) ) {
-				return new WP_Error( 'cdata_regex' );
-			}
-		}
-		return true;
-	}
-
-	/**
-	 * Determines is a node is currently valid per its tag specification.
-	 *
-	 * Checks to see if a node's placement with the DOM is be valid for the
-	 * given tag_spec. If there are restrictions placed on the type of node
-	 * that can be an immediate parent or an ancestor of this node, then make
-	 * sure those restrictions are met.
-	 *
-	 * @since 0.5
-	 *
-	 * @param DOMNode $node The node to validate.
-	 * @param array   $tag_spec The specification.
-	 * @return boolean $valid Whether the node's placement is valid.
-	 */
-	private function validate_tag_spec_for_node( $node, $tag_spec ) {
-
-		if ( ! empty( $tag_spec[ AMP_Rule_Spec::MANDATORY_PARENT ] ) && ! $this->has_parent( $node, $tag_spec[ AMP_Rule_Spec::MANDATORY_PARENT ] ) ) {
-			return false;
-		}
-
-		// Extension scripts must be in the head.
-		if ( isset( $tag_spec['extension_spec'] ) && ! $this->has_parent( $node, 'head' ) ) {
-			return false;
-		}
-
-		if ( ! empty( $tag_spec[ AMP_Rule_Spec::DISALLOWED_ANCESTOR ] ) ) {
-			foreach ( $tag_spec[ AMP_Rule_Spec::DISALLOWED_ANCESTOR ] as $disallowed_ancestor_node_name ) {
-				if ( $this->has_ancestor( $node, $disallowed_ancestor_node_name ) ) {
-					return false;
-				}
-			}
-		}
-
-		if ( ! empty( $tag_spec[ AMP_Rule_Spec::MANDATORY_ANCESTOR ] ) && ! $this->has_ancestor( $node, $tag_spec[ AMP_Rule_Spec::MANDATORY_ANCESTOR ] ) ) {
-			return false;
-		}
-
-		return true;
-	}
-
-	/**
-	 * Checks to see if a spec is potentially valid.
-	 *
-	 * Checks the given node based on the attributes present in the node.
-	 *
-	 * @note This can be a very expensive function. Use it sparingly.
-	 *
-	 * @param DOMNode $node           Node.
-	 * @param array[] $attr_spec_list Attribute Spec list.
-	 *
-	 * @return float Number of times the attribute spec list matched. If there was a mismatch, then 0 is returned. 0.5 is returned if there is an implicit match.
-	 */
-	private function validate_attr_spec_list_for_node( $node, $attr_spec_list ) {
-		/*
-		 * If node has no attributes there is no point in continuing, but if none of attributes
-		 * in the spec list are mandatory, then we give this a score.
-		 */
-		if ( ! $node->hasAttributes() ) {
-			foreach ( $attr_spec_list as $attr_name => $attr_spec_rule ) {
-				if ( isset( $attr_spec_rule[ AMP_Rule_Spec::MANDATORY ] ) ) {
-					return 0;
-				}
-			}
-			return 0.5;
-		}
-
-		if ( ! $node instanceof DOMElement ) {
-			/*
-			 * A DOMNode is not valid for checks so might
-			 * as well bail here is not an DOMElement.
-			 */
-			return 0;
-		}
-
-		foreach ( $node->attributes as $attr_name => $attr_node ) {
-			if ( ! isset( $attr_spec_list[ $attr_name ][ AMP_Rule_Spec::ALTERNATIVE_NAMES ] ) ) {
-				continue;
-			}
-			foreach ( $attr_spec_list[ $attr_name ][ AMP_Rule_Spec::ALTERNATIVE_NAMES ] as $attr_alt_name ) {
-				$attr_spec_list[ $attr_alt_name ] = $attr_spec_list[ $attr_name ];
-			}
-		}
-
-		$score = 0;
-
-		/*
-		 * Keep track of how many of the attribute spec rules are mandatory,
-		 * because if none are mandatory, then we will let this rule have a
-		 * score since all the invalid attributes can just be removed.
-		 */
-		$mandatory_count = 0;
-
-		/*
-		 * Iterate through each attribute rule in this attr spec list and run
-		 * the series of tests. Each filter is given a `$node`, an `$attr_name`,
-		 * and an `$attr_spec_rule`. If the `$attr_spec_rule` seems to be valid
-		 * for the given node, then the filter should increment the score by one.
-		 */
-		foreach ( $attr_spec_list as $attr_name => $attr_spec_rule ) {
-
-			// If attr spec rule is empty, then it allows anything.
-			if ( empty( $attr_spec_rule ) && $node->hasAttribute( $attr_name ) ) {
-				$score++;
-				continue;
-			}
-
-			// If a mandatory attribute is required, and attribute exists, pass.
-			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::MANDATORY ] ) ) {
-				$mandatory_count++;
-				$result = $this->check_attr_spec_rule_mandatory( $node, $attr_name, $attr_spec_rule );
-				if ( AMP_Rule_Spec::PASS === $result ) {
-					$score++;
-				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
-					return 0;
-				}
-			}
-
-			/*
-			 * Check 'value' - case sensitive
-			 * Given attribute's value must exactly equal value of the rule to pass.
-			 */
-			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE ] ) ) {
-				$result = $this->check_attr_spec_rule_value( $node, $attr_name, $attr_spec_rule );
-				if ( AMP_Rule_Spec::PASS === $result ) {
-					$score++;
-				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
-					return 0;
-				}
-			}
-
-			/*
-			 * Check 'value_regex' - case sensitive regex match
-			 * Given attribute's value must be a case insensitive match to regex pattern
-			 * specified by the value of rule to pass.
-			 */
-			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_REGEX ] ) ) {
-				$result = $this->check_attr_spec_rule_value_regex( $node, $attr_name, $attr_spec_rule );
-				if ( AMP_Rule_Spec::PASS === $result ) {
-					$score++;
-				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
-					return 0;
-				}
-			}
-
-			/*
-			 * Check 'value_casei' - case insensitive
-			 * Given attribute's value must be a case insensitive match to the value of
-			 * the rule to pass.
-			 */
-			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_CASEI ] ) ) {
-				$result = $this->check_attr_spec_rule_value_casei( $node, $attr_name, $attr_spec_rule );
-				if ( AMP_Rule_Spec::PASS === $result ) {
-					$score++;
-				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
-					return 0;
-				}
-			}
-
-			/*
-			 * Check 'value_regex_casei' - case insensitive regex match
-			 * Given attribute's value must be a case insensitive match to the regex
-			 * pattern specified by the value of the rule to pass.
-			 */
-			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_REGEX_CASEI ] ) ) {
-				$result = $this->check_attr_spec_rule_value_regex_casei( $node, $attr_name, $attr_spec_rule );
-				if ( AMP_Rule_Spec::PASS === $result ) {
-					$score++;
-				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
-					return 0;
-				}
-			}
-
-			/*
-			 * If given attribute's value is a URL with a protocol, the protocol must
-			 * be in the array specified by the rule's value to pass.
-			 */
-			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOWED_PROTOCOL ] ) ) {
-				$result = $this->check_attr_spec_rule_allowed_protocol( $node, $attr_name, $attr_spec_rule );
-				if ( AMP_Rule_Spec::PASS === $result ) {
-					$score++;
-				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
-					return 0;
-				}
-			}
-
-			/*
-			 * If given attribute's value is a URL with a host, the host must
-			 * be valid
-			 */
-			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ] ) ) {
-				$result = $this->check_attr_spec_rule_valid_url( $node, $attr_name, $attr_spec_rule );
-				if ( AMP_Rule_Spec::PASS === $result ) {
-					$score++;
-				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
-					return 0;
-				}
-			}
-
-			/*
-			 * If the given attribute's value is *not* a relative path, and the rule's
-			 * value is `false`, then pass.
-			 */
-			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOW_RELATIVE ] ) ) {
-				$result = $this->check_attr_spec_rule_disallowed_relative( $node, $attr_name, $attr_spec_rule );
-				if ( AMP_Rule_Spec::PASS === $result ) {
-					$score++;
-				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
-					return 0;
-				}
-			}
-
-			/*
-			 * If the given attribute's value exists, is non-empty and the rule's value
-			 * is false, then pass.
-			 */
-			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOW_EMPTY ] ) ) {
-				$result = $this->check_attr_spec_rule_disallowed_empty( $node, $attr_name, $attr_spec_rule );
-				if ( AMP_Rule_Spec::PASS === $result ) {
-					$score++;
-				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
-					return 0;
-				}
-			}
-
-			/*
-			 * If the given attribute's value is a URL and does not match any of the list
-			 * of domains in the value of the rule, then pass.
-			 */
-			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::DISALLOWED_DOMAIN ] ) ) {
-				$result = $this->check_attr_spec_rule_disallowed_domain( $node, $attr_name, $attr_spec_rule );
-				if ( AMP_Rule_Spec::PASS === $result ) {
-					$score++;
-				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
-					return 0;
-				}
-			}
-
-			/*
-			 * If the attribute's value exists and does not match the regex specified
-			 * by the rule's value, then pass.
-			 */
-			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::BLACKLISTED_VALUE_REGEX ] ) ) {
-				$result = $this->check_attr_spec_rule_blacklisted_value_regex( $node, $attr_name, $attr_spec_rule );
-				if ( AMP_Rule_Spec::PASS === $result ) {
-					$score++;
-				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
-					return 0;
-				}
-			}
-
-			// If the attribute's value exists and it matches the value properties spec.
-			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_PROPERTIES ] ) && $node->hasAttribute( $attr_name ) ) {
-				$result = $this->check_attr_spec_rule_value_properties( $node, $attr_name, $attr_spec_rule );
-				if ( AMP_Rule_Spec::PASS === $result ) {
-					$score++;
-				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
-					return 0;
-				}
-			}
-		}
-
-		// Give the spec a score if it doesn't have any mandatory attributes.
-		if ( 0 === $mandatory_count && 0 === $score ) {
-			$score = 0.5;
-		}
-
-		return $score;
-	}
-
-	/**
-	 * Remove attributes from $node that are not listed in $allowed_attrs.
-	 *
-	 * @param DOMNode $node           Node.
-	 * @param array[] $attr_spec_list Attribute spec list.
-	 * @return DOMAttr[] Attributes to remove.
-	 */
-	private function get_disallowed_attributes_in_node( $node, $attr_spec_list ) {
-
-		if ( ! $node instanceof DOMElement ) {
-			/**
-			 * If $node is only a DOMNode and not a DOMElement we can't
-			 * remove an attribute from it anyway.  So bail out now.
-			 */
-			return array();
-		}
-
-		/*
-		 * We can't remove attributes inside the 'foreach' loop without
-		 * breaking the iteration. So we keep track of the attributes to
-		 * remove in the first loop, then remove them in the second loop.
-		 */
-		$attrs_to_remove = array();
-		foreach ( $node->attributes as $attr_name => $attr_node ) {
-			if ( ! $this->is_amp_allowed_attribute( $attr_node, $attr_spec_list ) ) {
-				$attrs_to_remove[] = $attr_node;
-			}
-		}
-
-		return $attrs_to_remove;
-	}
-
-	/**
-	 * Remove invalid AMP attributes values from $node that have been implicitly disallowed.
-	 *
-	 * Allowed values are found $this->globally_allowed_attributes and in parameter $attr_spec_list
-	 *
-	 * @param DOMNode   $node                       Node.
-	 * @param array[][] $attr_spec_list             Attribute spec list.
-	 * @param DOMAttr[] $attributes_pending_removal Attributes pending removal.
-	 * @return DOMAttr[]|false Attributes to remove, or false if the element itself should be removed.
-	 */
-	private function sanitize_disallowed_attribute_values_in_node( $node, $attr_spec_list, $attributes_pending_removal ) {
-
-		if ( ! $node instanceof DOMElement ) {
-			/*
-			 * If $node is only a DOMNode and not a DOMElement we can't
-			 * remove an attribute from it anyway.  So bail out now.
-			 */
-			return $attributes_pending_removal;
-		}
-
-		return $this->delegated_sanitize_disallowed_attribute_values_in_node(
-			$node,
-			array_merge(
-				$this->globally_allowed_attributes,
-				$attr_spec_list
-			),
-			$attributes_pending_removal
-		);
-	}
-
-	/**
-	 * Remove attributes values from $node that have been disallowed by AMP.
-	 *
-	 * @see $this->sanitize_disallowed_attribute_values_in_node() which delegates to this method
-	 *
-	 * @param DOMElement $node                       Node.
-	 * @param array[][]  $attr_spec_list             Attribute spec list.
-	 * @param DOMAttr[]  $attributes_pending_removal Attributes pending removal.
-	 * @return DOMAttr[]|false Attributes to remove, or false if the element itself should be removed.
-	 */
-	private function delegated_sanitize_disallowed_attribute_values_in_node( $node, $attr_spec_list, $attributes_pending_removal ) {
-		$attrs_to_remove = array();
-
-		foreach ( $attr_spec_list as $attr_name => $attr_val ) {
-			if ( isset( $attr_spec_list[ $attr_name ][ AMP_Rule_Spec::ALTERNATIVE_NAMES ] ) ) {
-				foreach ( $attr_spec_list[ $attr_name ][ AMP_Rule_Spec::ALTERNATIVE_NAMES ] as $attr_alt_name ) {
-					$attr_spec_list[ $attr_alt_name ] = $attr_spec_list[ $attr_name ];
-				}
-			}
-		}
-
-		foreach ( $node->attributes as $attr_name => $attr_node ) {
-
-			if ( ! isset( $attr_spec_list[ $attr_name ] ) || in_array( $attr_node, $attributes_pending_removal, true ) ) {
-				continue;
-			}
-
-			$should_remove_node = false;
-			$attr_spec_rule     = $attr_spec_list[ $attr_name ];
-
-			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE ] ) &&
-				AMP_Rule_Spec::FAIL === $this->check_attr_spec_rule_value( $node, $attr_name, $attr_spec_rule ) ) {
-				$should_remove_node = true;
-			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_CASEI ] ) &&
-				AMP_Rule_Spec::FAIL === $this->check_attr_spec_rule_value_casei( $node, $attr_name, $attr_spec_rule ) ) {
-				$should_remove_node = true;
-			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_REGEX ] ) &&
-				AMP_Rule_Spec::FAIL === $this->check_attr_spec_rule_value_regex( $node, $attr_name, $attr_spec_rule ) ) {
-				$should_remove_node = true;
-			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_REGEX_CASEI ] ) &&
-				AMP_Rule_Spec::FAIL === $this->check_attr_spec_rule_value_regex_casei( $node, $attr_name, $attr_spec_rule ) ) {
-				$should_remove_node = true;
-			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOWED_PROTOCOL ] ) &&
-				AMP_Rule_Spec::FAIL === $this->check_attr_spec_rule_allowed_protocol( $node, $attr_name, $attr_spec_rule ) ) {
-				$should_remove_node = true;
-			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ] ) &&
-				AMP_Rule_Spec::FAIL === $this->check_attr_spec_rule_valid_url( $node, $attr_name, $attr_spec_rule ) ) {
-				$should_remove_node = true;
-			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOW_RELATIVE ] ) &&
-				AMP_Rule_Spec::FAIL === $this->check_attr_spec_rule_disallowed_relative( $node, $attr_name, $attr_spec_rule ) ) {
-				$should_remove_node = true;
-			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOW_EMPTY ] ) &&
-				AMP_Rule_Spec::FAIL === $this->check_attr_spec_rule_disallowed_empty( $node, $attr_name, $attr_spec_rule ) ) {
-				$should_remove_node = true;
-			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::DISALLOWED_DOMAIN ] ) &&
-				AMP_Rule_Spec::FAIL === $this->check_attr_spec_rule_disallowed_domain( $node, $attr_name, $attr_spec_rule ) ) {
-				$should_remove_node = true;
-			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::BLACKLISTED_VALUE_REGEX ] ) &&
-				AMP_Rule_Spec::FAIL === $this->check_attr_spec_rule_blacklisted_value_regex( $node, $attr_name, $attr_spec_rule ) ) {
-				$should_remove_node = true;
-			}
-
-			if ( $should_remove_node ) {
-				$is_mandatory =
-					isset( $attr_spec_rule[ AMP_Rule_Spec::MANDATORY ] )
-						? (bool) $attr_spec_rule[ AMP_Rule_Spec::MANDATORY ]
-						: false;
-
-				if ( $is_mandatory ) {
-					$this->remove_node( $node );
-					return false;
-				}
-
-				$attrs_to_remove[] = $attr_node;
-			}
-		}
-
-		// Remove the disallowed values.
-		foreach ( $attrs_to_remove as $attr_node ) {
-			if ( isset( $attr_spec_list[ $attr_node->nodeName ][ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOW_EMPTY ] ) &&
-				( true === $attr_spec_list[ $attr_node->nodeName ][ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOW_EMPTY ] ) ) {
-				$attr_node->nodeValue = '';
-			} else {
-				$attributes_pending_removal[] = $attr_node;
-			}
-		}
-
-		return $attributes_pending_removal;
-	}
-
-	/**
-	 * Check if attribute is mandatory determine whether it exists in $node.
-	 *
-	 * When checking for the given attribute it also checks valid alternates.
-	 *
-	 * @param DOMElement $node           Node.
-	 * @param string     $attr_name      Attribute name.
-	 * @param array[]    $attr_spec_rule Attribute spec rule.
-	 *
-	 * @return string:
-	 *      - AMP_Rule_Spec::PASS - $attr_name is mandatory and it exists
-	 *      - AMP_Rule_Spec::FAIL - $attr_name is mandatory, but doesn't exist
-	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name is not mandatory
-	 */
-	private function check_attr_spec_rule_mandatory( $node, $attr_name, $attr_spec_rule ) {
-		if ( isset( $attr_spec_rule[ AMP_Rule_Spec::MANDATORY ] ) && ( $attr_spec_rule[ AMP_Rule_Spec::MANDATORY ] ) ) {
-			if ( $node->hasAttribute( $attr_name ) ) {
-				return AMP_Rule_Spec::PASS;
-			} else {
-				// Check if an alternative name list is specified.
-				if ( isset( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] ) ) {
-					foreach ( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] as $alt_name ) {
-						if ( $node->hasAttribute( $alt_name ) ) {
-							return AMP_Rule_Spec::PASS;
-						}
-					}
-				}
-				return AMP_Rule_Spec::FAIL;
-			}
-		}
-		return AMP_Rule_Spec::NOT_APPLICABLE;
-	}
-
-	/**
-	 * Check if attribute has a value rule determine if its value is valid.
-	 *
-	 * Checks for value validity by matches against valid values.
-	 *
-	 * @param DOMElement $node           Node.
-	 * @param string     $attr_name      Attribute name.
-	 * @param array      $attr_spec_rule Attribute spec rule.
-	 *
-	 * @return string:
-	 *      - AMP_Rule_Spec::PASS - $attr_name has a value that matches the rule.
-	 *      - AMP_Rule_Spec::FAIL - $attr_name has a value that does *not* match rule.
-	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name does not exist or there
-	 *                                        is no rule for this attribute.
-	 */
-	private function check_attr_spec_rule_value( $node, $attr_name, $attr_spec_rule ) {
-		if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE ] ) ) {
-			if ( $node->hasAttribute( $attr_name ) ) {
-				if ( $this->check_matching_attribute_value( $attr_name, $node->getAttribute( $attr_name ), $attr_spec_rule[ AMP_Rule_Spec::VALUE ] ) ) {
-					return AMP_Rule_Spec::PASS;
-				} else {
-					return AMP_Rule_Spec::FAIL;
-				}
-			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] ) ) {
-				foreach ( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] as $alternative_name ) {
-					if ( $node->hasAttribute( $alternative_name ) ) {
-						if ( $this->check_matching_attribute_value( $attr_name, $node->getAttribute( $alternative_name ), $attr_spec_rule[ AMP_Rule_Spec::VALUE ] ) ) {
-							return AMP_Rule_Spec::PASS;
-						} else {
-							return AMP_Rule_Spec::FAIL;
-						}
-					}
-				}
-			}
-		}
-		return AMP_Rule_Spec::NOT_APPLICABLE;
-	}
-
-	/**
-	 * Check that an attribute's value matches is given spec value.
-	 *
-	 * This takes into account boolean attributes where value can match name (e.g. selected="selected").
-	 *
-	 * @since 0.7.0
-	 * @since 1.0.0 The spec value is now an array.
-	 *
-	 * @param string       $attr_name   Attribute name.
-	 * @param string       $attr_value  Attribute value.
-	 * @param string|array $spec_values Attribute spec value(s).
-	 * @return bool Is value valid.
-	 */
-	private function check_matching_attribute_value( $attr_name, $attr_value, $spec_values ) {
-		if ( is_string( $spec_values ) ) {
-			$spec_values = (array) $spec_values;
-		}
-		foreach ( $spec_values as $spec_value ) {
-			if ( $spec_value === $attr_value ) {
-				return true;
-			}
-
-			// Check for boolean attribute.
-			$is_bool_match = (
-				'' === $spec_value
-				&&
-				in_array( $attr_name, AMP_Rule_Spec::$boolean_attributes, true )
-				&&
-				strtolower( $attr_value ) === strtolower( $attr_name )
-			);
-			if ( $is_bool_match ) {
-				return true;
-			}
-		}
-		return false;
-	}
-
-	/**
-	 * Check if attribute has a value rule determine if its value matches ignoring case.
-	 *
-	 * @param DOMElement   $node           Node.
-	 * @param string       $attr_name      Attribute name.
-	 * @param array|string $attr_spec_rule Attribute spec rule.
-	 *
-	 * @return string:
-	 *      - AMP_Rule_Spec::PASS - $attr_name has a value that matches the rule.
-	 *      - AMP_Rule_Spec::FAIL - $attr_name has a value that does *not* match rule.
-	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name does not exist or there
-	 *                                        is no rule for this attribute.
-	 */
-	private function check_attr_spec_rule_value_casei( $node, $attr_name, $attr_spec_rule ) {
-		if ( ! isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_CASEI ] ) ) {
-			return AMP_Rule_Spec::NOT_APPLICABLE;
-		}
-
-		$result      = AMP_Rule_Spec::NOT_APPLICABLE;
-		$rule_values = (array) $attr_spec_rule[ AMP_Rule_Spec::VALUE_CASEI ];
-		foreach ( $rule_values as $rule_value ) {
-			$rule_value = strtolower( $rule_value );
-			if ( $node->hasAttribute( $attr_name ) ) {
-				$attr_value = strtolower( $node->getAttribute( $attr_name ) );
-				if ( $attr_value === (string) $rule_value ) {
-					return AMP_Rule_Spec::PASS;
-				} else {
-					$result = AMP_Rule_Spec::FAIL;
-				}
-			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] ) ) {
-				foreach ( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] as $alternative_name ) {
-					if ( $node->hasAttribute( $alternative_name ) ) {
-						$attr_value = strtolower( $node->getAttribute( $alternative_name ) );
-						if ( $attr_value === (string) $rule_value ) {
-							return AMP_Rule_Spec::PASS;
-						} else {
-							$result = AMP_Rule_Spec::FAIL;
-						}
-					}
-				}
-			}
-		}
-		return $result;
-	}
-
-	/**
-	 * Check if attribute has a regex value rule determine if it matches.
-	 *
-	 * @param DOMElement       $node           Node.
-	 * @param string           $attr_name      Attribute name.
-	 * @param array[]|string[] $attr_spec_rule Attribute spec rule.
-	 *
-	 * @return string:
-	 *      - AMP_Rule_Spec::PASS - $attr_name has a value that matches the rule.
-	 *      - AMP_Rule_Spec::FAIL - $attr_name has a value that does *not* match rule.
-	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name does not exist or there
-	 *                                        is no rule for this attribute.
-	 */
-	private function check_attr_spec_rule_value_regex( $node, $attr_name, $attr_spec_rule ) {
-		// Check 'value_regex' - case sensitive regex match.
-		if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_REGEX ] ) && $node->hasAttribute( $attr_name ) ) {
-			$rule_value = $attr_spec_rule[ AMP_Rule_Spec::VALUE_REGEX ];
-			$rule_value = str_replace( '/', '\\/', $rule_value );
-
-			/*
-			 * The regex pattern has '^' and '$' though they are not in the AMP spec.
-			 * Leaving them out would allow both '_blank' and 'yyy_blankzzz' to be
-			 * matched by a regex rule of '(_blank|_self|_top)'. As the AMP JS validator
-			 * only accepts '_blank' we leave it this way for now.
-			 */
-			if ( preg_match( '/^(' . $rule_value . ')$/u', $node->getAttribute( $attr_name ) ) ) {
-				return AMP_Rule_Spec::PASS;
-			} else {
-				return AMP_Rule_Spec::FAIL;
-			}
-		}
-		return AMP_Rule_Spec::NOT_APPLICABLE;
-	}
-
-	/**
-	 * Check if attribute has a case-insensitive regex value rule determine if it matches.
-	 *
-	 * @param DOMElement       $node           Node.
-	 * @param string           $attr_name      Attribute name.
-	 * @param array[]|string[] $attr_spec_rule Attribute spec rule.
-	 *
-	 * @return string:
-	 *      - AMP_Rule_Spec::PASS - $attr_name has a value that matches the rule.
-	 *      - AMP_Rule_Spec::FAIL - $attr_name has a value that does *not* match rule.
-	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name does not exist or there
-	 *                                        is no rule for this attribute.
-	 */
-	private function check_attr_spec_rule_value_regex_casei( $node, $attr_name, $attr_spec_rule ) {
-		/**
-		 * Check 'value_regex_casei' - case insensitive regex match
-		 */
-		if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_REGEX_CASEI ] ) && $node->hasAttribute( $attr_name ) ) {
-			$rule_value = $attr_spec_rule[ AMP_Rule_Spec::VALUE_REGEX_CASEI ];
-			$rule_value = str_replace( '/', '\\/', $rule_value );
-
-			// See note above regarding the '^' and '$' that are added here.
-			if ( preg_match( '/^(' . $rule_value . ')$/ui', $node->getAttribute( $attr_name ) ) ) {
-				return AMP_Rule_Spec::PASS;
-			} else {
-				return AMP_Rule_Spec::FAIL;
-			}
-		}
-		return AMP_Rule_Spec::NOT_APPLICABLE;
-	}
-
-	/**
-	 * Check if attribute has a valid host value
-	 *
-	 * @since 0.7
-	 *
-	 * @param DOMElement       $node           Node.
-	 * @param string           $attr_name      Attribute name.
-	 * @param array[]|string[] $attr_spec_rule Attribute spec rule.
-	 *
-	 * @return string:
-	 *      - AMP_Rule_Spec::PASS - $attr_name has a value that matches the rule.
-	 *      - AMP_Rule_Spec::FAIL - $attr_name has a value that does *not* match rule.
-	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name does not exist or there
-	 *                                        is no rule for this attribute.
-	 */
-	private function check_attr_spec_rule_valid_url( $node, $attr_name, $attr_spec_rule ) {
-		if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ] ) ) {
-			if ( $node->hasAttribute( $attr_name ) ) {
-				foreach ( $this->extract_attribute_urls( $node->getAttributeNode( $attr_name ) ) as $url ) {
-					$url = urldecode( $url );
-
-					// Check if the protocol contains invalid chars (protocolCharIsValid: https://github.com/ampproject/amphtml/blob/af1e3a550feeafd732226202b8d1f26dcefefa18/validator/engine/parse-url.js#L31-L39).
-					$protocol = $this->parse_protocol( $url );
-					if ( isset( $protocol ) ) {
-						if ( ! preg_match( '/^[a-zA-Z0-9\+-]+/i', $protocol ) ) {
-							return AMP_Rule_Spec::FAIL;
-						}
-						$url = substr( $url, strlen( $protocol ) + 1 );
-					}
-
-					// Check if the host contains invalid chars (hostCharIsValid: https://github.com/ampproject/amphtml/blob/af1e3a550feeafd732226202b8d1f26dcefefa18/validator/engine/parse-url.js#L62-L103).
-					$host = wp_parse_url( $url, PHP_URL_HOST );
-					if ( $host && preg_match( '/[!"#$%&\'()*+,\/:;<=>?@[\]^`{|}~\s]/i', $host ) ) {
-						return AMP_Rule_Spec::FAIL;
-					}
-				}
-
-				return AMP_Rule_Spec::PASS;
-			}
-		}
-
-		return AMP_Rule_Spec::NOT_APPLICABLE;
-	}
-
-	/**
-	 * Parse protocol from URL.
-	 *
-	 * This may not be a valid protocol (scheme), but it will be where the protocol should be in the URL.
-	 *
-	 * @link https://github.com/ampproject/amphtml/blob/af1e3a550feeafd732226202b8d1f26dcefefa18/validator/engine/parse-url.js#L235-L282
-	 * @param string $url URL.
-	 * @return string|null Protocol without colon if matched. Otherwise null.
-	 */
-	private function parse_protocol( $url ) {
-		if ( preg_match( '#^[^/]+(?=:)#', $url, $matches ) ) {
-			return $matches[0];
-		}
-		return null;
-	}
-
-	/**
-	 * Check if attribute has a protocol value rule determine if it matches.
-	 *
-	 * @param DOMElement       $node           Node.
-	 * @param string           $attr_name      Attribute name.
-	 * @param array[]|string[] $attr_spec_rule Attribute spec rule.
-	 *
-	 * @return string:
-	 *      - AMP_Rule_Spec::PASS - $attr_name has a value that matches the rule.
-	 *      - AMP_Rule_Spec::FAIL - $attr_name has a value that does *not* match rule.
-	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name does not exist or there
-	 *                                        is no rule for this attribute.
-	 */
-	private function check_attr_spec_rule_allowed_protocol( $node, $attr_name, $attr_spec_rule ) {
-		if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOWED_PROTOCOL ] ) ) {
-			if ( $node->hasAttribute( $attr_name ) ) {
-				foreach ( $this->extract_attribute_urls( $node->getAttributeNode( $attr_name ) ) as $url ) {
-					$url_scheme = $this->parse_protocol( $url );
-					if ( isset( $url_scheme ) && ! in_array( strtolower( $url_scheme ), $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOWED_PROTOCOL ], true ) ) {
-						return AMP_Rule_Spec::FAIL;
-					}
-				}
-				return AMP_Rule_Spec::PASS;
-			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] ) ) {
-				foreach ( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] as $alternative_name ) {
-					if ( $node->hasAttribute( $alternative_name ) ) {
-						foreach ( $this->extract_attribute_urls( $node->getAttributeNode( $alternative_name ), $attr_name ) as $url ) {
-							$url_scheme = $this->parse_protocol( $url );
-							if ( isset( $url_scheme ) && ! in_array( strtolower( $url_scheme ), $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOWED_PROTOCOL ], true ) ) {
-								return AMP_Rule_Spec::FAIL;
-							}
-						}
-						return AMP_Rule_Spec::PASS;
-					}
-				}
-			}
-		}
-		return AMP_Rule_Spec::NOT_APPLICABLE;
-	}
-
-	/**
-	 * Extract URLs from attribute.
-	 *
-	 * @param DOMAttr     $attribute_node Attribute node.
-	 * @param string|null $spec_attr_name Non-alternative attribute name for the spec.
-	 * @return string[] List of URLs.
-	 */
-	private function extract_attribute_urls( $attribute_node, $spec_attr_name = null ) {
-		/*
-		 * Handle the srcset special case where the attribute value can contain multiple parts, each in the format `URL [WIDTH] [PIXEL_DENSITY]`.
-		 * So we split the srcset attribute value by commas and then return the first token of each item, omitting width descriptor and pixel density descriptor.
-		 * This splitting cannot be done for other URLs because it a comma can appear in a URL itself generally, but the syntax can break in srcset,
-		 * unless the commas are URL-encoded.
-		 */
-		if ( 'srcset' === $attribute_node->nodeName || 'srcset' === $spec_attr_name ) {
-			return array_filter( array_map(
-				function ( $srcset_part ) {
-					// Remove descriptors for width and pixel density.
-					return preg_replace( '/\s.*$/', '', trim( $srcset_part ) );
-				},
-				preg_split( '/\s*,\s*/', $attribute_node->nodeValue )
-			) );
-		} else {
-			return array( $attribute_node->nodeValue );
-		}
-	}
-
-	/**
-	 * Check if attribute has disallowed relative URL value according to rule spec.
-	 *
-	 * @param DOMElement       $node           Node.
-	 * @param string           $attr_name      Attribute name.
-	 * @param array[]|string[] $attr_spec_rule Attribute spec rule.
-	 *
-	 * @return string:
-	 *      - AMP_Rule_Spec::PASS - $attr_name has a value that matches the rule.
-	 *      - AMP_Rule_Spec::FAIL - $attr_name has a value that does *not* match rule.
-	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name does not exist or there
-	 *                                        is no rule for this attribute.
-	 */
-	private function check_attr_spec_rule_disallowed_relative( $node, $attr_name, $attr_spec_rule ) {
-		if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOW_RELATIVE ] ) && ! ( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOW_RELATIVE ] ) ) {
-			if ( $node->hasAttribute( $attr_name ) ) {
-				foreach ( $this->extract_attribute_urls( $node->getAttributeNode( $attr_name ) ) as $url ) {
-					$parsed_url = wp_parse_url( $url );
-
-					/*
-					 *  The JS AMP validator seems to consider 'relative' to mean
-					 *  *protocol* relative, not *host* relative for this rule. So,
-					 *  a url with an empty 'scheme' is considered "relative" by AMP.
-					 *  ie. '//domain.com/path' and '/path' should both be considered
-					 *  relative for purposes of AMP validation.
-					 */
-					if ( empty( $parsed_url['scheme'] ) ) {
-						return AMP_Rule_Spec::FAIL;
-					}
-				}
-				return AMP_Rule_Spec::PASS;
-			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] ) ) {
-				foreach ( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] as $alternative_name ) {
-					if ( $node->hasAttribute( $alternative_name ) ) {
-						foreach ( $this->extract_attribute_urls( $node->getAttributeNode( $alternative_name ), $attr_name ) as $url ) {
-							$parsed_url = wp_parse_url( $url );
-							if ( empty( $parsed_url['scheme'] ) ) {
-								return AMP_Rule_Spec::FAIL;
-							}
-						}
-					}
-				}
-				return AMP_Rule_Spec::PASS;
-			}
-		}
-		return AMP_Rule_Spec::NOT_APPLICABLE;
-	}
-
-	/**
-	 * Check if attribute has disallowed empty value rule determine if value is empty.
-	 *
-	 * @param DOMElement       $node           Node.
-	 * @param string           $attr_name      Attribute name.
-	 * @param array[]|string[] $attr_spec_rule Attribute spec rule.
-	 *
-	 * @return string:
-	 *      - AMP_Rule_Spec::PASS - $attr_name has a value that matches the rule.
-	 *      - AMP_Rule_Spec::FAIL - $attr_name has a value that does *not* match rule.
-	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name does not exist or there
-	 *                                        is no rule for this attribute.
-	 */
-	private function check_attr_spec_rule_disallowed_empty( $node, $attr_name, $attr_spec_rule ) {
-		if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOW_EMPTY ] ) && ! ( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOW_EMPTY ] ) && $node->hasAttribute( $attr_name ) ) {
-			$attr_value = $node->getAttribute( $attr_name );
-			if ( empty( $attr_value ) ) {
-				return AMP_Rule_Spec::FAIL;
-			}
-			return AMP_Rule_Spec::PASS;
-		}
-		return AMP_Rule_Spec::NOT_APPLICABLE;
-	}
-
-	/**
-	 * Check if attribute has disallowed domain value rule determine if value matches.
-	 *
-	 * @param DOMElement       $node           Node.
-	 * @param string           $attr_name      Attribute name.
-	 * @param array[]|string[] $attr_spec_rule Attribute spec rule.
-	 *
-	 * @return string:
-	 *      - AMP_Rule_Spec::PASS - $attr_name has a value that matches the rule.
-	 *      - AMP_Rule_Spec::FAIL - $attr_name has a value that does *not* match rule.
-	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name does not exist or there
-	 *                                        is no rule for this attribute.
-	 */
-	private function check_attr_spec_rule_disallowed_domain( $node, $attr_name, $attr_spec_rule ) {
-		if ( isset( $attr_spec_rule[ AMP_Rule_Spec::DISALLOWED_DOMAIN ] ) && $node->hasAttribute( $attr_name ) ) {
-			$attr_value = $node->getAttribute( $attr_name );
-			$url_domain = wp_parse_url( $attr_value, PHP_URL_HOST );
-			if ( ! empty( $url_domain ) ) {
-				foreach ( $attr_spec_rule[ AMP_Rule_Spec::DISALLOWED_DOMAIN ] as $disallowed_domain ) {
-					if ( strtolower( $url_domain ) === strtolower( $disallowed_domain ) ) {
-
-						// Found a disallowed domain, fail validation.
-						return AMP_Rule_Spec::FAIL;
-					}
-				}
-				return AMP_Rule_Spec::PASS;
-			}
-		}
-		return AMP_Rule_Spec::NOT_APPLICABLE;
-	}
-
-	/**
-	 * Check if attribute has blacklisted value via regex match determine if value matches.
-	 *
-	 * @since 0.5
-	 *
-	 * @param DOMElement       $node           Node.
-	 * @param string           $attr_name      Attribute name.
-	 * @param array[]|string[] $attr_spec_rule Attribute spec rule.
-	 *
-	 * @return string:
-	 *      - AMP_Rule_Spec::PASS - $attr_name has a value that matches the rule.
-	 *      - AMP_Rule_Spec::FAIL - $attr_name has a value that does *not* match rule.
-	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name does not exist or there
-	 *                                        is no rule for this attribute.
-	 */
-	private function check_attr_spec_rule_blacklisted_value_regex( $node, $attr_name, $attr_spec_rule ) {
-		if ( isset( $attr_spec_rule[ AMP_Rule_Spec::BLACKLISTED_VALUE_REGEX ] ) ) {
-			$pattern = '/' . $attr_spec_rule[ AMP_Rule_Spec::BLACKLISTED_VALUE_REGEX ] . '/u';
-			if ( $node->hasAttribute( $attr_name ) ) {
-				$attr_value = $node->getAttribute( $attr_name );
-				if ( preg_match( $pattern, $attr_value ) ) {
-					return AMP_Rule_Spec::FAIL;
-				} else {
-					return AMP_Rule_Spec::PASS;
-				}
-			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] ) ) {
-				foreach ( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] as $alternative_name ) {
-					if ( $node->hasAttribute( $alternative_name ) ) {
-						$attr_value = $node->getAttribute( $alternative_name );
-						if ( preg_match( $pattern, $attr_value ) ) {
-							return AMP_Rule_Spec::FAIL;
-						} else {
-							return AMP_Rule_Spec::PASS;
-						}
-					}
-				}
-			}
-		}
-		return AMP_Rule_Spec::NOT_APPLICABLE;
-	}
-
-	/**
-	 * Check if attribute has valid properties.
-	 *
-	 * @since 0.7
-	 *
-	 * @param DOMElement       $node           Node.
-	 * @param string           $attr_name      Attribute name.
-	 * @param array[]|string[] $attr_spec_rule Attribute spec rule.
-	 *
-	 * @return string:
-	 *      - AMP_Rule_Spec::PASS - $attr_name has a value that matches the rule.
-	 *      - AMP_Rule_Spec::FAIL - $attr_name has a value that does *not* match rule.
-	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name does not exist or there
-	 *                                        is no rule for this attribute.
-	 */
-	private function check_attr_spec_rule_value_properties( $node, $attr_name, $attr_spec_rule ) {
-		if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_PROPERTIES ] ) && $node->hasAttribute( $attr_name ) ) {
-			$properties = array();
-			foreach ( explode( ',', $node->getAttribute( $attr_name ) ) as $pair ) {
-				$pair_parts = explode( '=', $pair, 2 );
-				if ( 2 !== count( $pair_parts ) ) {
-					return 0;
-				}
-				$properties[ trim( strtolower( $pair_parts[0] ) ) ] = trim( $pair_parts[1] );
-			}
-
-			// Fail if there are unrecognized properties.
-			if ( count( array_diff( array_keys( $properties ), array_keys( $attr_spec_rule[ AMP_Rule_Spec::VALUE_PROPERTIES ] ) ) ) > 0 ) {
-				return AMP_Rule_Spec::FAIL;
-			}
-
-			foreach ( $attr_spec_rule[ AMP_Rule_Spec::VALUE_PROPERTIES ] as $prop_name => $property_spec ) {
-
-				// Mandatory property is missing.
-				if ( ! empty( $property_spec['mandatory'] ) && ! isset( $properties[ $prop_name ] ) ) {
-					return AMP_Rule_Spec::FAIL;
-				}
-
-				if ( ! isset( $properties[ $prop_name ] ) ) {
-					continue;
-				}
-
-				$prop_value = $properties[ $prop_name ];
-
-				// Required value is absent, so fail.
-				$required_value = null;
-				if ( isset( $property_spec['value'] ) ) {
-					$required_value = $property_spec['value'];
-				} elseif ( isset( $property_spec['value_double'] ) ) {
-					$required_value = $property_spec['value_double'];
-					$prop_value     = (double) $prop_value;
-				}
-				if ( isset( $required_value ) && $prop_value !== $required_value ) {
-					return AMP_Rule_Spec::FAIL;
-				}
-			}
-			return AMP_Rule_Spec::PASS;
-		}
-		return AMP_Rule_Spec::NOT_APPLICABLE;
-	}
-
-	/**
-	 * Determine if the supplied attribute name is allowed for AMP.
-	 *
-	 * @since 0.5
-	 *
-	 * @param DOMAttr          $attr_node      Attribute node.
-	 * @param array[]|string[] $attr_spec_list Attribute spec list.
-	 * @return bool Return true if attribute name is valid for this attr_spec_list, false otherwise.
-	 */
-	private function is_amp_allowed_attribute( $attr_node, $attr_spec_list ) {
-		$attr_name = $attr_node->nodeName;
-		if (
-			isset( $attr_spec_list[ $attr_name ] )
-			||
-			'data-' === substr( $attr_name, 0, 5 )
-			||
-			// Allow the 'amp' or '⚡' attribute in <html>, like <html ⚡>.
-			( 'html' === $attr_node->parentNode->nodeName && in_array( $attr_node->nodeName, array( 'amp', '⚡' ), true ) )
-		) {
-			return true;
-		}
-
-		$is_allowed_alt_name_attr = (
-			isset( $this->rev_alternate_attr_name_lookup[ $attr_name ] )
-			&&
-			isset( $attr_spec_list[ $this->rev_alternate_attr_name_lookup[ $attr_name ] ] )
-		);
-		if ( $is_allowed_alt_name_attr ) {
-			return true;
-		}
-
-		/*
-		 * Handle special case for amp-selector where its reference points do not have to be direct children.
-		 * This is noted as a special case in the AMP validator spec for amp-selector, so that is why it is
-		 * a special case here in this method. It is also implemented in this way for the sake of efficiency
-		 * to prevent having to waste time in process_node() merging attribute lists. For more on amp-selector's
-		 * unique reference point, see:
-		 * https://github.com/ampproject/amphtml/blob/1526498116488/extensions/amp-selector/validator-amp-selector.protoascii#L81-L91
-		 */
-		$reference_point_spec = AMP_Allowed_Tags_Generated::get_reference_point_spec( 'AMP-SELECTOR option' );
-		if ( isset( $reference_point_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ][ $attr_name ] ) ) {
-			$parent = $attr_node->parentNode;
-			while ( $parent ) {
-				if ( 'amp-selector' === $parent->nodeName ) {
-					return true;
-				}
-				$parent = $parent->parentNode;
-			}
-		}
-
-		return false;
-	}
-
-	/**
-	 * Determine if the supplied $node's HTML tag is allowed for AMP.
-	 *
-	 * @since 0.5
-	 *
-	 * @param DOMNode $node Node.
-	 * @return bool Return true if the specified node's name is an AMP allowed tag, false otherwise.
-	 */
-	private function is_amp_allowed_tag( $node ) {
-		if ( ! $node instanceof DOMElement ) {
-			return false;
-		}
-		/**
-		 * Return true if node is an allowed tags or is a text or comment node.
-		 */
-		return (
-			( XML_TEXT_NODE === $node->nodeType ) ||
-			isset( $this->allowed_tags[ $node->nodeName ] ) ||
-			( XML_COMMENT_NODE === $node->nodeType ) ||
-			( XML_CDATA_SECTION_NODE === $node->nodeType )
-		);
-	}
-
-	/**
-	 * Determine if the supplied $node has a parent with the specified spec name.
-	 *
-	 * @since 0.5
-	 *
-	 * @todo It would be more robust if the the actual tag spec were looked up and then matched against the parent, but this is currently overkill.
-	 *
-	 * @param DOMNode $node             Node.
-	 * @param string  $parent_spec_name Parent spec name, for example 'body' or 'form [method=post]'.
-	 * @return bool Return true if given node has direct parent with the given name, false otherwise.
-	 */
-	private function has_parent( $node, $parent_spec_name ) {
-		if ( ! $node ) {
-			return false;
-		}
-		$parsed_spec_name = $this->parse_tag_and_attributes_from_spec_name( $parent_spec_name );
-
-		if ( ! $node->parentNode || $node->parentNode->nodeName !== $parsed_spec_name['tag_name'] ) {
-			return false;
-		}
-
-		// Ensure attributes match; if not move up to the next node.
-		foreach ( $parsed_spec_name['attributes'] as $attr_name => $attr_value ) {
-			if ( $node instanceof DOMElement && strtolower( $node->getAttribute( $attr_name ) ) !== $attr_value ) {
-				return false;
-			}
-		}
-
-		return true;
-	}
-
-	/**
-	 * Determine if the supplied $node has an ancestor with the specified tag name.
-	 *
-	 * @since 0.5
-	 *
-	 * @param DOMNode $node              Node.
-	 * @param string  $ancestor_tag_name Ancestor tag name.
-	 * @return bool Return true if given node has any ancestor with the give name, false otherwise.
-	 */
-	private function has_ancestor( $node, $ancestor_tag_name ) {
-		if ( $this->get_ancestor_with_matching_spec_name( $node, $ancestor_tag_name ) ) {
-			return true;
-		}
-		return false;
-	}
-
-	/**
-	 * Parse tag name and attributes from spec name.
-	 *
-	 * Given a spec name like 'form [method=post]', extract the tag name 'form' and the attributes.
-	 *
-	 * @todo This is admittedly rudimentary. It would be more robust to actually look up the tag spec by the name and obtain the required attributes from there, but this is not necessary yet.
-	 *
-	 * @param string $spec_name Spec name.
-	 * @return array Tag name and attributes.
-	 */
-	private function parse_tag_and_attributes_from_spec_name( $spec_name ) {
-		static $parsed_specs = array();
-		if ( isset( $parsed_specs[ $spec_name ] ) ) {
-			return $parsed_specs[ $spec_name ];
-		}
-
-		$attributes = array();
-
-		/*
-		 * This matches spec names like:
-		 * - body
-		 * - form [method=post]
-		 * - form > div [submit-error][template]
-		 */
-		if ( preg_match( '/^(?P<ancestors>.+? )?(?P<tag_name>[a-z0-9_-]+?)( (?P<raw_attrs>\[.+?\]))?$/i', $spec_name, $matches ) ) {
-			$tag_name = $matches['tag_name'];
-
-			if ( isset( $matches['raw_attrs'] ) ) {
-				$raw_attr_pairs = explode( '][', trim( $matches['raw_attrs'], '[]' ) );
-				foreach ( $raw_attr_pairs as $raw_attr_pair ) {
-					$raw_attr_pair = explode( '=', $raw_attr_pair );
-
-					$attr_key = $raw_attr_pair[0];
-					$attr_val = isset( $raw_attr_pair[1] ) ? $raw_attr_pair[1] : true;
-
-					$attributes[ $attr_key ] = $attr_val;
-				}
-			}
-		} else {
-			$tag_name = strtok( $spec_name, ' ' ); // Fallback case.
-		}
-
-		$parsed_specs[ $spec_name ] = compact( 'tag_name', 'attributes' );
-		return $parsed_specs[ $spec_name ];
-	}
-
-	/**
-	 * Get the first ancestor node matching the specified tag name for the supplied $node.
-	 *
-	 * @since 0.5
-	 * @todo It would be more robust if the the actual tag spec were looked up and then matched for each ancestor, but this is currently overkill.
-	 *
-	 * @param DOMNode $node               Node.
-	 * @param string  $ancestor_spec_name Ancestor spec name, e.g. 'body' or 'form [method=post]'.
-	 * @return DOMNode|null Returns an ancestor node for the name specified, or null if not found.
-	 */
-	private function get_ancestor_with_matching_spec_name( $node, $ancestor_spec_name ) {
-		$parsed_spec_name = $this->parse_tag_and_attributes_from_spec_name( $ancestor_spec_name );
-
-		while ( $node && $node->parentNode ) {
-			$node = $node->parentNode;
-			if ( $node->nodeName === $parsed_spec_name['tag_name'] ) {
-
-				// Ensure attributes match; if not move up to the next node.
-				foreach ( $parsed_spec_name['attributes'] as $attr_name => $attr_value ) {
-					$match = (
-						$node instanceof DOMElement
-						&&
-						true === $attr_value ? $node->hasAttribute( $attr_name ) : strtolower( $node->getAttribute( $attr_name ) ) === $attr_value
-					);
-					if ( ! $match ) {
-						continue 2;
-					}
-				}
-
-				return $node;
-			}
-		}
-		return null;
-	}
-
-	/**
-	 * Replaces the given node with it's child nodes, if any
-	 *
-	 * Also adds them to the stack for processing by the sanitize() function.
-	 *
-	 * @since 0.3.3
-	 * @since 1.0 Fix silently removing unrecognized elements.
-	 * @see https://github.com/Automattic/amp-wp/issues/1100
-	 *
-	 * @param DOMNode $node Node.
-	 */
-	private function replace_node_with_children( $node ) {
-
-		// If node has no children or no parent, just remove the node.
-		if ( ! $node->hasChildNodes() || ! $node->parentNode ) {
-			$this->remove_node( $node );
-
-			return;
-		}
-
-		/*
-		 * If node has children, replace it with them and push children onto stack
-		 *
-		 * Create a DOM fragment to hold the children
-		 */
-		$fragment = $this->dom->createDocumentFragment();
-
-		// Add all children to fragment/stack.
-		$child = $node->firstChild;
-		while ( $child ) {
-			$fragment->appendChild( $child );
-			$this->stack[] = $child;
-			$child         = $node->firstChild;
-		}
-
-		// Prevent double-reporting nodes that are rejected for sanitization.
-		if ( isset( $this->should_not_replace_nodes[ $node->nodeName ] ) && in_array( $node, $this->should_not_replace_nodes[ $node->nodeName ], true ) ) {
-			return;
-		}
-
-		// Replace node with fragment.
-		$should_replace = $this->should_sanitize_validation_error( array(), compact( 'node' ) );
-		if ( $should_replace ) {
-			$node->parentNode->replaceChild( $fragment, $node );
-		} else {
-			$this->should_not_replace_nodes[ $node->nodeName ][] = $node;
-		}
-	}
-
-	/**
-	 * Removes a node from its parent node.
-	 *
-	 * If removing the node makes the parent node empty, then it will remove the parent
-	 * too. It will Continue until a non-empty parent or the 'body' element is reached.
-	 *
-	 * @since 0.5
-	 *
-	 * @param DOMNode $node Node.
-	 */
-	private function remove_node( $node ) {
-		/**
-		 * Parent.
-		 *
-		 * @var DOMNode $parent
-		 */
-		$parent = $node->parentNode;
-		if ( $node && $parent ) {
-			$this->remove_invalid_child( $node );
-		}
-		while ( $parent && ! $parent->hasChildNodes() && $this->root_element !== $parent ) {
-			$node   = $parent;
-			$parent = $parent->parentNode;
-			if ( $parent ) {
-				$parent->removeChild( $node );
-			}
-		}
-	}
-}
diff --git a/includes/sanitizers/class-amp-video-sanitizer.php b/includes/sanitizers/class-amp-video-sanitizer.php
deleted file mode 100644
index 201975e631c..00000000000
--- a/includes/sanitizers/class-amp-video-sanitizer.php
+++ /dev/null
@@ -1,231 +0,0 @@
-<?php
-/**
- * Class AMP_Video_Sanitizer.
- *
- * @package AMP
- */
-
-/**
- * Class AMP_Video_Sanitizer
- *
- * @since 0.2
- *
- * Converts <video> tags to <amp-video>
- */
-class AMP_Video_Sanitizer extends AMP_Base_Sanitizer {
-
-	/**
-	 * Value used for height attribute when $attributes['height'] is empty.
-	 *
-	 * @since 0.2
-	 *
-	 * @const int
-	 */
-	const FALLBACK_HEIGHT = 400;
-
-	/**
-	 * Tag.
-	 *
-	 * @var string HTML <video> tag to identify and replace with AMP version.
-	 *
-	 * @since 0.2
-	 */
-	public static $tag = 'video';
-
-	/**
-	 * Get mapping of HTML selectors to the AMP component selectors which they may be converted into.
-	 *
-	 * @return array Mapping.
-	 */
-	public function get_selector_conversion_mapping() {
-		return array(
-			'video' => array( 'amp-video', 'amp-youtube' ),
-		);
-	}
-
-	/**
-	 * Sanitize the <video> elements from the HTML contained in this instance's DOMDocument.
-	 *
-	 * @since 0.2
-	 * @since 1.0 Set the filtered child node's src attribute.
-	 */
-	public function sanitize() {
-		$nodes     = $this->dom->getElementsByTagName( self::$tag );
-		$num_nodes = $nodes->length;
-		if ( 0 === $num_nodes ) {
-			return;
-		}
-
-		for ( $i = $num_nodes - 1; $i >= 0; $i-- ) {
-			$node           = $nodes->item( $i );
-			$amp_data       = $this->get_data_amp_attributes( $node );
-			$old_attributes = AMP_DOM_Utils::get_node_attributes_as_assoc_array( $node );
-			$old_attributes = $this->filter_data_amp_attributes( $old_attributes, $amp_data );
-
-			$sources_count  = 0;
-			$new_attributes = $this->filter_attributes( $old_attributes );
-			$layout         = isset( $amp_data['layout'] ) ? $amp_data['layout'] : false;
-			if ( isset( $new_attributes['src'] ) ) {
-				$new_attributes = $this->filter_video_dimensions( $new_attributes, $new_attributes['src'] );
-				if ( $new_attributes['src'] ) {
-					$sources_count++;
-				}
-			}
-
-			// Gather all child nodes and supply empty video dimensions from sources.
-			$fallback    = null;
-			$child_nodes = array();
-			while ( $node->firstChild ) {
-				$child_node = $node->removeChild( $node->firstChild );
-				if ( $child_node instanceof DOMElement && 'source' === $child_node->nodeName && $child_node->hasAttribute( 'src' ) ) {
-					$src = $this->maybe_enforce_https_src( $child_node->getAttribute( 'src' ), true );
-					if ( ! $src ) {
-						// @todo $this->remove_invalid_child( $child_node ), but this will require refactoring the while loop since it uses firstChild.
-						continue; // Skip adding source.
-					}
-					$sources_count++;
-					$child_node->setAttribute( 'src', $src );
-					$new_attributes = $this->filter_video_dimensions( $new_attributes, $src );
-				}
-
-				if ( ! $fallback && $child_node instanceof DOMElement && ! ( 'source' === $child_node->nodeName || 'track' === $child_node->nodeName ) ) {
-					$fallback = $child_node;
-					$fallback->setAttribute( 'fallback', '' );
-				}
-
-				$child_nodes[] = $child_node;
-			}
-
-			$new_attributes = $this->filter_attachment_layout_attributes( $node, $new_attributes, $layout );
-			if ( empty( $new_attributes['layout'] ) && ! empty( $new_attributes['width'] ) && ! empty( $new_attributes['height'] ) ) {
-				$new_attributes['layout'] = 'responsive';
-			}
-			$new_attributes = $this->set_layout( $new_attributes );
-
-			// @todo Make sure poster and artwork attributes are HTTPS.
-			$new_node = AMP_DOM_Utils::create_node( $this->dom, 'amp-video', $new_attributes );
-			foreach ( $child_nodes as $child_node ) {
-				$new_node->appendChild( $child_node );
-			}
-
-			/*
-			 * If the node has at least one valid source, replace the old node with it.
-			 * Otherwise, just remove the node.
-			 *
-			 * TODO: Add a fallback handler.
-			 * See: https://github.com/ampproject/amphtml/issues/2261
-			 */
-			if ( 0 === $sources_count ) {
-				$this->remove_invalid_child( $node );
-			} else {
-				$node->parentNode->replaceChild( $new_node, $node );
-			}
-
-			$this->did_convert_elements = true;
-
-		}
-	}
-
-	/**
-	 * Filter video dimensions, try to get width and height from original file if missing.
-	 *
-	 * @param array  $new_attributes Attributes.
-	 * @param string $src            Video URL.
-	 * @return array Modified attributes.
-	 */
-	protected function filter_video_dimensions( $new_attributes, $src ) {
-		if ( empty( $new_attributes['width'] ) || empty( $new_attributes['height'] ) ) {
-
-			// Get the width and height from the file.
-			$path = wp_parse_url( $src, PHP_URL_PATH );
-			$ext  = pathinfo( $path, PATHINFO_EXTENSION );
-			$name = sanitize_title( wp_basename( $path, ".$ext" ) );
-			$args = array(
-				'name'        => $name,
-				'post_type'   => 'attachment',
-				'post_status' => 'inherit',
-				'numberposts' => 1,
-			);
-
-			$attachment = get_posts( $args );
-
-			if ( ! empty( $attachment ) ) {
-				$meta_data = wp_get_attachment_metadata( $attachment[0]->ID );
-				if ( empty( $new_attributes['width'] ) && ! empty( $meta_data['width'] ) ) {
-					$new_attributes['width'] = $meta_data['width'];
-				}
-				if ( empty( $new_attributes['height'] ) && ! empty( $meta_data['height'] ) ) {
-					$new_attributes['height'] = $meta_data['height'];
-				}
-			}
-		}
-
-		return $new_attributes;
-	}
-
-	/**
-	 * "Filter" HTML attributes for <amp-audio> elements.
-	 *
-	 * @since 0.2
-	 * @since 1.0 Force HTTPS for the src attribute.
-	 *
-	 * @param string[] $attributes {
-	 *      Attributes.
-	 *
-	 *      @type string    $src        Video URL - Empty if HTTPS required per $this->args['require_https_src']
-	 *      @type int       $width      <video> attribute - Set to numeric value if px or %
-	 *      @type int       $height     <video> attribute - Set to numeric value if px or %
-	 *      @type string    $poster     <video> attribute - Pass along if found
-	 *      @type string    $class      <video> attribute - Pass along if found
-	 *      @type bool      $controls   <video> attribute - Convert 'false' to empty string ''
-	 *      @type bool      $loop       <video> attribute - Convert 'false' to empty string ''
-	 *      @type bool      $muted      <video> attribute - Convert 'false' to empty string ''
-	 *      @type bool      $autoplay   <video> attribute - Convert 'false' to empty string ''
-	 * }
-	 * @return array Returns HTML attributes; removes any not specifically declared above from input.
-	 */
-	private function filter_attributes( $attributes ) {
-		$out = array();
-
-		foreach ( $attributes as $name => $value ) {
-			switch ( $name ) {
-				case 'src':
-					$out[ $name ] = $this->maybe_enforce_https_src( $value, true );
-					break;
-
-				case 'width':
-				case 'height':
-					$out[ $name ] = $this->sanitize_dimension( $value, $name );
-					break;
-
-				// @todo Convert to HTTPS when is_ssl().
-				case 'poster':
-				case 'artwork':
-					$out[ $name ] = $value;
-					break;
-
-				case 'controls':
-				case 'loop':
-				case 'muted':
-				case 'autoplay':
-					if ( 'false' !== $value ) {
-						$out[ $name ] = '';
-					}
-					break;
-
-				case 'data-amp-layout':
-					$out['layout'] = $value;
-					break;
-
-				case 'data-amp-noloading':
-					$out['noloading'] = $value;
-					break;
-
-				default:
-					$out[ $name ] = $value;
-			}
-		}
-
-		return $out;
-	}
-}

From a95b903599308876e56104090a7fdb13256ab624 Mon Sep 17 00:00:00 2001
From: Marcelo Vani <marcellovani@yahoo.co.uk>
Date: Thu, 29 Nov 2018 16:39:36 +0000
Subject: [PATCH 08/17] Re-instated includes

---
 includes/class-amp-autoloader.php             |    2 +-
 .../sanitizers/class-amp-audio-sanitizer.php  |  172 ++
 .../sanitizers/class-amp-base-sanitizer.php   |  583 +++++
 .../class-amp-blacklist-sanitizer.php         |  301 +++
 .../sanitizers/class-amp-block-sanitizer.php  |  133 +
 .../class-amp-comments-sanitizer.php          |  156 ++
 .../class-amp-core-theme-sanitizer.php        | 1107 ++++++++
 .../sanitizers/class-amp-embed-sanitizer.php  |   47 +
 .../sanitizers/class-amp-form-sanitizer.php   |  156 ++
 .../class-amp-gallery-block-sanitizer.php     |  207 ++
 .../sanitizers/class-amp-iframe-sanitizer.php |  196 ++
 .../sanitizers/class-amp-img-sanitizer.php    |  376 +++
 .../class-amp-o2-player-sanitizer.php         |  140 ++
 .../class-amp-playbuzz-sanitizer.php          |  146 ++
 includes/sanitizers/class-amp-rule-spec.php   |  139 +
 .../sanitizers/class-amp-script-sanitizer.php |   49 +
 .../sanitizers/class-amp-style-sanitizer.php  | 2225 +++++++++++++++++
 .../class-amp-tag-and-attribute-sanitizer.php | 1874 ++++++++++++++
 .../sanitizers/class-amp-video-sanitizer.php  |  231 ++
 19 files changed, 8239 insertions(+), 1 deletion(-)
 create mode 100644 includes/sanitizers/class-amp-audio-sanitizer.php
 create mode 100644 includes/sanitizers/class-amp-base-sanitizer.php
 create mode 100644 includes/sanitizers/class-amp-blacklist-sanitizer.php
 create mode 100644 includes/sanitizers/class-amp-block-sanitizer.php
 create mode 100644 includes/sanitizers/class-amp-comments-sanitizer.php
 create mode 100644 includes/sanitizers/class-amp-core-theme-sanitizer.php
 create mode 100644 includes/sanitizers/class-amp-embed-sanitizer.php
 create mode 100644 includes/sanitizers/class-amp-form-sanitizer.php
 create mode 100644 includes/sanitizers/class-amp-gallery-block-sanitizer.php
 create mode 100644 includes/sanitizers/class-amp-iframe-sanitizer.php
 create mode 100644 includes/sanitizers/class-amp-img-sanitizer.php
 create mode 100644 includes/sanitizers/class-amp-o2-player-sanitizer.php
 create mode 100644 includes/sanitizers/class-amp-playbuzz-sanitizer.php
 create mode 100644 includes/sanitizers/class-amp-rule-spec.php
 create mode 100644 includes/sanitizers/class-amp-script-sanitizer.php
 create mode 100644 includes/sanitizers/class-amp-style-sanitizer.php
 create mode 100644 includes/sanitizers/class-amp-tag-and-attribute-sanitizer.php
 create mode 100644 includes/sanitizers/class-amp-video-sanitizer.php

diff --git a/includes/class-amp-autoloader.php b/includes/class-amp-autoloader.php
index 2d3c8725742..a93305d01e9 100644
--- a/includes/class-amp-autoloader.php
+++ b/includes/class-amp-autoloader.php
@@ -71,7 +71,7 @@ class AMP_Autoloader {
 		'AMP_Analytics_Options_Submenu_Page'          => 'includes/options/views/class-amp-analytics-options-submenu-page',
 		'AMP_Options_Menu_Page'                       => 'includes/options/views/class-amp-options-menu-page',
 		'AMP_Rule_Spec'                               => 'includes/sanitizers/class-amp-rule-spec',
-		'AMP_Allowed_Tags_Generated'                  => 'includes/sanitizers/class-amp-allowed-tags-generated',
+//		'AMP_Allowed_Tags_Generated'                  => 'includes/sanitizers/class-amp-allowed-tags-generated',
 		'AMP_Audio_Sanitizer'                         => 'includes/sanitizers/class-amp-audio-sanitizer',
 		'AMP_Base_Sanitizer'                          => 'includes/sanitizers/class-amp-base-sanitizer',
 		'AMP_Blacklist_Sanitizer'                     => 'includes/sanitizers/class-amp-blacklist-sanitizer',
diff --git a/includes/sanitizers/class-amp-audio-sanitizer.php b/includes/sanitizers/class-amp-audio-sanitizer.php
new file mode 100644
index 00000000000..3622ccb2208
--- /dev/null
+++ b/includes/sanitizers/class-amp-audio-sanitizer.php
@@ -0,0 +1,172 @@
+<?php
+/**
+ * Class AMP_Audio_Sanitizer
+ *
+ * @package AMP
+ */
+
+/**
+ * Class AMP_Audio_Sanitizer
+ *
+ * Converts <audio> tags to <amp-audio>
+ */
+class AMP_Audio_Sanitizer extends AMP_Base_Sanitizer {
+
+	/**
+	 * Tag.
+	 *
+	 * @var string HTML audio tag to identify and replace with AMP version.
+	 * @since 0.2
+	 */
+	public static $tag = 'audio';
+
+	/**
+	 * Get mapping of HTML selectors to the AMP component selectors which they may be converted into.
+	 *
+	 * @return array Mapping.
+	 */
+	public function get_selector_conversion_mapping() {
+		return array(
+			'audio' => array( 'amp-audio' ),
+		);
+	}
+
+	/**
+	 * Sanitize the <audio> elements from the HTML contained in this instance's DOMDocument.
+	 *
+	 * @since 0.2
+	 */
+	public function sanitize() {
+		$nodes     = $this->dom->getElementsByTagName( self::$tag );
+		$num_nodes = $nodes->length;
+		if ( 0 === $num_nodes ) {
+			return;
+		}
+
+		for ( $i = $num_nodes - 1; $i >= 0; $i-- ) {
+			$node           = $nodes->item( $i );
+			$amp_data       = $this->get_data_amp_attributes( $node );
+			$old_attributes = AMP_DOM_Utils::get_node_attributes_as_assoc_array( $node );
+			$old_attributes = $this->filter_data_amp_attributes( $old_attributes, $amp_data );
+
+			$new_attributes = $this->filter_attributes( $old_attributes );
+
+			$new_node = AMP_DOM_Utils::create_node( $this->dom, 'amp-audio', $new_attributes );
+
+			foreach ( $node->childNodes as $child_node ) {
+
+				/**
+				 * Child node.
+				 *
+				 * @todo: Fix when `source` has no closing tag as DOMDocument does not handle well.
+				 *
+				 * @var DOMNode $child_node
+				 */
+
+				$new_child_node = $child_node->cloneNode( true );
+				if ( ! $new_child_node instanceof DOMElement ) {
+					continue;
+				}
+
+				$old_child_attributes = AMP_DOM_Utils::get_node_attributes_as_assoc_array( $new_child_node );
+				$new_child_attributes = $this->filter_attributes( $old_child_attributes );
+
+				if ( empty( $new_child_attributes['src'] ) ) {
+					continue;
+				}
+				if ( 'source' !== $new_child_node->tagName ) {
+					continue;
+				}
+
+				// The textContent is invalid for `source` nodes.
+				$new_child_node->textContent = null;
+
+				// Only append source tags with a valid src attribute.
+				$new_node->appendChild( $new_child_node );
+
+			}
+
+			/**
+			 * If the node has at least one valid source, replace the old node with it.
+			 * Otherwise, just remove the node.
+			 *
+			 * @todo: Add a fallback handler.
+			 * @see: https://github.com/ampproject/amphtml/issues/2261
+			 */
+			if ( 0 === $new_node->childNodes->length && empty( $new_attributes['src'] ) ) {
+				$this->remove_invalid_child( $node );
+			} else {
+
+				$layout = isset( $new_attributes['layout'] ) ? $new_attributes['layout'] : false;
+
+				// The width has to be unset / auto in case of fixed-height.
+				if ( 'fixed-height' === $layout ) {
+					$new_node->setAttribute( 'width', 'auto' );
+				}
+
+				$node->parentNode->replaceChild( $new_node, $node );
+			}
+
+			$this->did_convert_elements = true;
+		}
+	}
+
+	/**
+	 * "Filter" HTML attributes for <amp-audio> elements.
+	 *
+	 * @since 0.2
+	 *
+	 * @param string[] $attributes {
+	 *      Attributes.
+	 *
+	 *      @type string $src Audio URL - Empty if HTTPS required per $this->args['require_https_src']
+	 *      @type int $width <audio> attribute - Set to numeric value if px or %
+	 *      @type int $height <audio> attribute - Set to numeric value if px or %
+	 *      @type string $class <audio> attribute - Pass along if found
+	 *      @type bool $loop <audio> attribute - Convert 'false' to empty string ''
+	 *      @type bool $muted <audio> attribute - Convert 'false' to empty string ''
+	 *      @type bool $autoplay <audio> attribute - Convert 'false' to empty string ''
+	 * }
+	 * @return array Returns HTML attributes; removes any not specifically declared above from input.
+	 */
+	private function filter_attributes( $attributes ) {
+		$out = array();
+
+		foreach ( $attributes as $name => $value ) {
+			switch ( $name ) {
+				case 'src':
+					$out[ $name ] = $this->maybe_enforce_https_src( $value );
+					break;
+
+				case 'width':
+				case 'height':
+					$out[ $name ] = $this->sanitize_dimension( $value, $name );
+					break;
+
+				case 'class':
+					$out[ $name ] = $value;
+					break;
+				case 'loop':
+				case 'muted':
+				case 'autoplay':
+					if ( 'false' !== $value ) {
+						$out[ $name ] = '';
+					}
+					break;
+
+				case 'data-amp-layout':
+					$out['layout'] = $value;
+					break;
+
+				case 'data-amp-noloading':
+					$out['noloading'] = $value;
+					break;
+
+				default:
+					break;
+			}
+		}
+
+		return $out;
+	}
+}
diff --git a/includes/sanitizers/class-amp-base-sanitizer.php b/includes/sanitizers/class-amp-base-sanitizer.php
new file mode 100644
index 00000000000..5319a9f7dce
--- /dev/null
+++ b/includes/sanitizers/class-amp-base-sanitizer.php
@@ -0,0 +1,583 @@
+<?php
+/**
+ * Class AMP_Base_Sanitizer
+ *
+ * @package AMP
+ */
+
+/**
+ * Class AMP_Base_Sanitizer
+ */
+abstract class AMP_Base_Sanitizer {
+
+	/**
+	 * Value used with the height attribute in an $attributes parameter is empty.
+	 *
+	 * @since 0.3.3
+	 *
+	 * @const int
+	 */
+	const FALLBACK_HEIGHT = 400;
+
+	/**
+	 * Value for <amp-image-lightbox> ID.
+	 *
+	 * @since 1.0
+	 *
+	 * @const string
+	 */
+	const AMP_IMAGE_LIGHTBOX_ID = 'amp-image-lightbox';
+
+	/**
+	 * Placeholder for default args, to be set in child classes.
+	 *
+	 * @since 0.2
+	 *
+	 * @var array
+	 */
+	protected $DEFAULT_ARGS = array();
+
+	/**
+	 * DOM.
+	 *
+	 * @var DOMDocument A standard PHP representation of an HTML document in object form.
+	 *
+	 * @since 0.2
+	 */
+	protected $dom;
+
+	/**
+	 * Array of flags used to control sanitization.
+	 *
+	 * @var array {
+	 *      @type int $content_max_width
+	 *      @type bool $add_placeholder
+	 *      @type bool $use_document_element
+	 *      @type bool $require_https_src
+	 *      @type string[] $amp_allowed_tags
+	 *      @type string[] $amp_globally_allowed_attributes
+	 *      @type string[] $amp_layout_allowed_attributes
+	 *      @type array $amp_allowed_tags
+	 *      @type array $amp_globally_allowed_attributes
+	 *      @type array $amp_layout_allowed_attributes
+	 *      @type array $amp_bind_placeholder_prefix
+	 *      @type bool $allow_dirty_styles
+	 *      @type bool $allow_dirty_scripts
+	 *      @type bool $should_locate_sources
+	 *      @type callable $validation_error_callback
+	 * }
+	 */
+	protected $args;
+
+	/**
+	 * Flag to be set in child class' sanitize() method indicating if the
+	 * HTML contained in the DOMDocument has been sanitized yet or not.
+	 *
+	 * @since 0.2
+	 *
+	 * @var bool
+	 */
+	protected $did_convert_elements = false;
+
+	/**
+	 * The root element used for sanitization. Either html or body.
+	 *
+	 * @var DOMElement
+	 */
+	protected $root_element;
+
+	/**
+	 * Keep track of nodes that should not be removed to prevent duplicated validation errors since sanitization is rejected.
+	 *
+	 * @var array
+	 */
+	private $should_not_removed_nodes = array();
+
+	/**
+	 * AMP_Base_Sanitizer constructor.
+	 *
+	 * @since 0.2
+	 *
+	 * @param DOMDocument $dom Represents the HTML document to sanitize.
+	 * @param array       $args {
+	 *      Args.
+	 *
+	 *      @type int $content_max_width
+	 *      @type bool $add_placeholder
+	 *      @type bool $require_https_src
+	 *      @type string[] $amp_allowed_tags
+	 *      @type string[] $amp_globally_allowed_attributes
+	 *      @type string[] $amp_layout_allowed_attributes
+	 * }
+	 */
+	public function __construct( $dom, $args = array() ) {
+		$this->dom  = $dom;
+		$this->args = array_merge( $this->DEFAULT_ARGS, $args );
+
+		if ( ! empty( $this->args['use_document_element'] ) ) {
+			$this->root_element = $this->dom->documentElement;
+		} else {
+			$this->root_element = $this->dom->getElementsByTagName( 'body' )->item( 0 );
+		}
+	}
+
+	/**
+	 * Add filters to manipulate output during output buffering before the DOM is constructed.
+	 *
+	 * Add actions and filters before the page is rendered so that the sanitizer can fix issues during output buffering.
+	 * This provides an alternative to manipulating the DOM in the sanitize method. This is a static function because
+	 * it is invoked before the class is instantiated, as the DOM is not available yet. This method is only called
+	 * when 'amp' theme support is present. It is conceptually similar to the AMP_Base_Embed_Handler class's register_embed
+	 * method.
+	 *
+	 * @since 1.0
+	 * @see \AMP_Base_Embed_Handler::register_embed()
+	 *
+	 * @param array $args Args.
+	 */
+	public static function add_buffering_hooks( $args = array() ) {}
+
+	/**
+	 * Get mapping of HTML selectors to the AMP component selectors which they may be converted into.
+	 *
+	 * @return array Mapping.
+	 */
+	public function get_selector_conversion_mapping() {
+		return array();
+	}
+
+	/**
+	 * Run logic before any sanitizers are run.
+	 *
+	 * After the sanitizers are instantiated but before calling sanitize on each of them, this
+	 * method is called with list of all the instantiated sanitizers.
+	 *
+	 * @param AMP_Base_Sanitizer[] $sanitizers Sanitizers.
+	 */
+	public function init( $sanitizers ) {}
+
+	/**
+	 * Sanitize the HTML contained in the DOMDocument received by the constructor
+	 */
+	abstract public function sanitize();
+
+	/**
+	 * Return array of values that would be valid as an HTML `script` element.
+	 *
+	 * Array keys are AMP element names and array values are their respective
+	 * Javascript URLs from https://cdn.ampproject.org
+	 *
+	 * @since 0.2
+	 *
+	 * @return string[] Returns component name as array key and JavaScript URL as array value,
+	 *                  respectively. Will return an empty array if sanitization has yet to be run
+	 *                  or if it did not find any HTML elements to convert to AMP equivalents.
+	 */
+	public function get_scripts() {
+		return array();
+	}
+
+	/**
+	 * Return array of values that would be valid as an HTML `style` attribute.
+	 *
+	 * @since 0.4
+	 * @deprecated As of 1.0, use get_stylesheets().
+	 *
+	 * @return array[][] Mapping of CSS selectors to arrays of properties.
+	 */
+	public function get_styles() {
+		return array();
+	}
+
+	/**
+	 * Get stylesheets.
+	 *
+	 * @since 0.7
+	 * @returns array Values are the CSS stylesheets. Keys are MD5 hashes of the stylesheets.
+	 */
+	public function get_stylesheets() {
+		$stylesheets = array();
+
+		foreach ( $this->get_styles() as $selector => $properties ) {
+			$stylesheet = sprintf( '%s { %s }', $selector, join( '; ', $properties ) . ';' );
+
+			$stylesheets[ md5( $stylesheet ) ] = $stylesheet;
+		}
+
+		return $stylesheets;
+	}
+
+	/**
+	 * Get HTML body as DOMElement from DOMDocument received by the constructor.
+	 *
+	 * @deprecated Just reference $root_element instead.
+	 * @return DOMElement The body element.
+	 */
+	protected function get_body_node() {
+		return $this->dom->getElementsByTagName( 'body' )->item( 0 );
+	}
+
+	/**
+	 * Sanitizes a CSS dimension specifier while being sensitive to dimension context.
+	 *
+	 * @param string $value A valid CSS dimension specifier; e.g. 50, 50px, 50%.
+	 * @param string $dimension 'width' or ignored. 'width' only affects $values ending in '%'.
+	 *
+	 * @return float|int|string Returns a numeric dimension value, or an empty string.
+	 */
+	public function sanitize_dimension( $value, $dimension ) {
+
+		// Allows 0 to be used as valid dimension.
+		if ( null === $value ) {
+			return '';
+		}
+
+		// Accepts both integers and floats & prevents negative values.
+		if ( is_numeric( $value ) ) {
+			return max( 0, floatval( $value ) );
+		}
+
+		if ( AMP_String_Utils::endswith( $value, 'px' ) ) {
+			return absint( $value );
+		}
+
+		if ( AMP_String_Utils::endswith( $value, '%' ) ) {
+			if ( 'width' === $dimension && isset( $this->args['content_max_width'] ) ) {
+				$percentage = absint( $value ) / 100;
+				return round( $percentage * $this->args['content_max_width'] );
+			}
+		}
+
+		return '';
+	}
+
+	/**
+	 * Sets the layout, and possibly the 'height' and 'width' attributes.
+	 *
+	 * @param string[] $attributes {
+	 *      Attributes.
+	 *
+	 *      @type int $height
+	 *      @type int $width
+	 *      @type string $sizes
+	 *      @type string $class
+	 *      @type string $layout
+	 * }
+	 * @return array Attributes.
+	 */
+	public function set_layout( $attributes ) {
+		if ( isset( $attributes['layout'] ) && ( 'fill' === $attributes['layout'] || 'flex-item' !== $attributes['layout'] ) ) {
+			return $attributes;
+		}
+		if ( empty( $attributes['height'] ) ) {
+			unset( $attributes['width'] );
+			$attributes['height'] = self::FALLBACK_HEIGHT;
+		}
+		if ( empty( $attributes['width'] ) ) {
+			$attributes['layout'] = 'fixed-height';
+		}
+
+		return $attributes;
+	}
+
+	/**
+	 * Adds or appends key and value to list of attributes
+	 *
+	 * Adds key and value to list of attributes, or if the key already exists in the array
+	 * it concatenates to existing attribute separator by a space or other supplied separator.
+	 *
+	 * @param string[] $attributes {
+	 *      Attributes.
+	 *
+	 *      @type int $height
+	 *      @type int $width
+	 *      @type string $sizes
+	 *      @type string $class
+	 *      @type string $layout
+	 * }
+	 * @param string   $key       Valid associative array index to add.
+	 * @param string   $value     Value to add or append to array indexed at the key.
+	 * @param string   $separator Optional; defaults to space but some other separator if needed.
+	 */
+	public function add_or_append_attribute( &$attributes, $key, $value, $separator = ' ' ) {
+		if ( isset( $attributes[ $key ] ) ) {
+			$attributes[ $key ] = trim( $attributes[ $key ] . $separator . $value );
+		} else {
+			$attributes[ $key ] = $value;
+		}
+	}
+
+	/**
+	 * Decide if we should remove a src attribute if https is required.
+	 *
+	 * If not required, the implementing class may want to try and force https instead.
+	 *
+	 * @param string  $src         URL to convert to HTTPS if forced, or made empty if $args['require_https_src'].
+	 * @param boolean $force_https Force setting of HTTPS if true.
+	 * @return string URL which may have been updated with HTTPS, or may have been made empty.
+	 */
+	public function maybe_enforce_https_src( $src, $force_https = false ) {
+		$protocol = strtok( $src, ':' ); // @todo What about relative URLs? This should use wp_parse_url( $src, PHP_URL_SCHEME )
+		if ( 'https' !== $protocol ) {
+			// Check if https is required.
+			if ( isset( $this->args['require_https_src'] ) && true === $this->args['require_https_src'] ) {
+				// Remove the src. Let the implementing class decide what do from here.
+				$src = '';
+			} elseif ( ( ! isset( $this->args['require_https_src'] ) || false === $this->args['require_https_src'] )
+				&& true === $force_https ) {
+				// Don't remove the src, but force https instead.
+				$src = set_url_scheme( $src, 'https' );
+			}
+		}
+
+		return $src;
+	}
+
+	/**
+	 * Removes an invalid child of a node.
+	 *
+	 * Also, calls the mutation callback for it.
+	 * This tracks all the nodes that were removed.
+	 *
+	 * @since 0.7
+	 *
+	 * @param DOMNode|DOMElement $node             The node to remove.
+	 * @param array              $validation_error Validation error details.
+	 * @return bool Whether the node should have been removed, that is, that the node was sanitized for validity.
+	 */
+	public function remove_invalid_child( $node, $validation_error = array() ) {
+
+		// Prevent double-reporting nodes that are rejected for sanitization.
+		if ( isset( $this->should_not_removed_nodes[ $node->nodeName ] ) && in_array( $node, $this->should_not_removed_nodes[ $node->nodeName ], true ) ) {
+			return false;
+		}
+
+		$should_remove = $this->should_sanitize_validation_error( $validation_error, compact( 'node' ) );
+		if ( $should_remove ) {
+			$node->parentNode->removeChild( $node );
+		} else {
+			$this->should_not_removed_nodes[ $node->nodeName ][] = $node;
+		}
+		return $should_remove;
+	}
+
+	/**
+	 * Removes an invalid attribute of a node.
+	 *
+	 * Also, calls the mutation callback for it.
+	 * This tracks all the attributes that were removed.
+	 *
+	 * @since 0.7
+	 *
+	 * @param DOMElement     $element   The node for which to remove the attribute.
+	 * @param DOMAttr|string $attribute The attribute to remove from the element.
+	 * @param array          $validation_error Validation error details.
+	 * @return bool Whether the node should have been removed, that is, that the node was sanitized for validity.
+	 */
+	public function remove_invalid_attribute( $element, $attribute, $validation_error = array() ) {
+		if ( is_string( $attribute ) ) {
+			$node = $element->getAttributeNode( $attribute );
+		} else {
+			$node = $attribute;
+		}
+		$should_remove = $this->should_sanitize_validation_error( $validation_error, compact( 'node' ) );
+		if ( $should_remove ) {
+			$element->removeAttributeNode( $node );
+		}
+		return $should_remove;
+	}
+
+	/**
+	 * Check whether or not sanitization should occur in response to validation error.
+	 *
+	 * @since 1.0
+	 *
+	 * @param array $validation_error Validation error.
+	 * @param array $data             Data including the node.
+	 * @return bool Whether to sanitize.
+	 */
+	public function should_sanitize_validation_error( $validation_error, $data = array() ) {
+		if ( empty( $this->args['validation_error_callback'] ) || ! is_callable( $this->args['validation_error_callback'] ) ) {
+			return true;
+		}
+		$validation_error = $this->prepare_validation_error( $validation_error, $data );
+		return false !== call_user_func( $this->args['validation_error_callback'], $validation_error, $data );
+	}
+
+	/**
+	 * Prepare validation error.
+	 *
+	 * @param array $error {
+	 *     Error.
+	 *
+	 *     @type string $code Error code.
+	 * }
+	 * @param array $data {
+	 *     Data.
+	 *
+	 *     @type DOMElement|DOMNode $node The removed node.
+	 * }
+	 * @return array Error.
+	 */
+	public function prepare_validation_error( array $error = array(), array $data = array() ) {
+		$node    = null;
+		$matches = null;
+
+		if ( isset( $data['node'] ) && $data['node'] instanceof DOMNode ) {
+			$node = $data['node'];
+
+			$error['node_name'] = $node->nodeName;
+			if ( $node->parentNode ) {
+				$error['parent_name'] = $node->parentNode->nodeName;
+			}
+		}
+
+		if ( $node instanceof DOMElement ) {
+			if ( ! isset( $error['code'] ) ) {
+				$error['code'] = AMP_Validation_Error_Taxonomy::INVALID_ELEMENT_CODE;
+			}
+
+			if ( ! isset( $error['type'] ) ) {
+				$error['type'] = 'script' === $node->nodeName ? AMP_Validation_Error_Taxonomy::JS_ERROR_TYPE : AMP_Validation_Error_Taxonomy::HTML_ELEMENT_ERROR_TYPE;
+			}
+
+			if ( ! isset( $error['node_attributes'] ) ) {
+				$error['node_attributes'] = array();
+				foreach ( $node->attributes as $attribute ) {
+					$error['node_attributes'][ $attribute->nodeName ] = $attribute->nodeValue;
+				}
+			}
+
+			// Capture script contents.
+			if ( 'script' === $node->nodeName && ! $node->hasAttribute( 'src' ) ) {
+				$error['text'] = $node->textContent;
+			}
+
+			// Suppress 'ver' param from enqueued scripts and styles.
+			if ( 'script' === $node->nodeName && isset( $error['node_attributes']['src'] ) && false !== strpos( $error['node_attributes']['src'], 'ver=' ) ) {
+				$error['node_attributes']['src'] = add_query_arg( 'ver', '__normalized__', $error['node_attributes']['src'] );
+			} elseif ( 'link' === $node->nodeName && isset( $error['node_attributes']['href'] ) && false !== strpos( $error['node_attributes']['href'], 'ver=' ) ) {
+				$error['node_attributes']['href'] = add_query_arg( 'ver', '__normalized__', $error['node_attributes']['href'] );
+			}
+		} elseif ( $node instanceof DOMAttr ) {
+			if ( ! isset( $error['code'] ) ) {
+				$error['code'] = AMP_Validation_Error_Taxonomy::INVALID_ATTRIBUTE_CODE;
+			}
+			if ( ! isset( $error['type'] ) ) {
+				// If this is an attribute that begins with on, like onclick, it should be a js_error.
+				$error['type'] = preg_match( '/^on\w+/', $node->nodeName ) ? AMP_Validation_Error_Taxonomy::JS_ERROR_TYPE : AMP_Validation_Error_Taxonomy::HTML_ATTRIBUTE_ERROR_TYPE;
+			}
+			if ( ! isset( $error['element_attributes'] ) ) {
+				$error['element_attributes'] = array();
+				if ( $node->parentNode && $node->parentNode->hasAttributes() ) {
+					foreach ( $node->parentNode->attributes as $attribute ) {
+						$error['element_attributes'][ $attribute->nodeName ] = $attribute->nodeValue;
+					}
+				}
+			}
+		}
+
+		return $error;
+	}
+
+	/**
+	 * Get data-amp-* values from the parent node 'figure' added by editor block.
+	 *
+	 * @param DOMElement $node Base node.
+	 * @return array AMP data array.
+	 */
+	public function get_data_amp_attributes( $node ) {
+		$attributes = array();
+
+		// Editor blocks add 'figure' as the parent node for images. If this node has data-amp-layout then we should add this as the layout attribute.
+		$parent_node = $node->parentNode;
+		if ( 'figure' === $parent_node->tagName ) {
+			$parent_attributes = AMP_DOM_Utils::get_node_attributes_as_assoc_array( $parent_node );
+			if ( isset( $parent_attributes['data-amp-layout'] ) ) {
+				$attributes['layout'] = $parent_attributes['data-amp-layout'];
+			}
+			if ( isset( $parent_attributes['data-amp-noloading'] ) && true === filter_var( $parent_attributes['data-amp-noloading'], FILTER_VALIDATE_BOOLEAN ) ) {
+				$attributes['noloading'] = $parent_attributes['data-amp-noloading'];
+			}
+		}
+
+		return $attributes;
+	}
+
+	/**
+	 * Set AMP attributes.
+	 *
+	 * @param array $attributes Array of attributes.
+	 * @param array $amp_data Array of AMP attributes.
+	 * @return array Updated attributes.
+	 */
+	public function filter_data_amp_attributes( $attributes, $amp_data ) {
+		if ( isset( $amp_data['layout'] ) ) {
+			$attributes['data-amp-layout'] = $amp_data['layout'];
+		}
+		if ( isset( $amp_data['noloading'] ) ) {
+			$attributes['data-amp-noloading'] = '';
+		}
+		return $attributes;
+	}
+
+	/**
+	 * Set attributes to node's parent element according to layout.
+	 *
+	 * @param DOMElement $node Node.
+	 * @param array      $new_attributes Attributes array.
+	 * @param string     $layout Layout.
+	 * @return array New attributes.
+	 */
+	public function filter_attachment_layout_attributes( $node, $new_attributes, $layout ) {
+
+		// The width has to be unset / auto in case of fixed-height.
+		if ( 'fixed-height' === $layout ) {
+			if ( ! isset( $new_attributes['height'] ) ) {
+				$new_attributes['height'] = self::FALLBACK_HEIGHT;
+			}
+			$new_attributes['width'] = 'auto';
+			$node->parentNode->setAttribute( 'style', 'height: ' . $new_attributes['height'] . 'px; width: auto;' );
+
+			// The parent element should have width/height set and position set in case of 'fill'.
+		} elseif ( 'fill' === $layout ) {
+			if ( ! isset( $new_attributes['height'] ) ) {
+				$new_attributes['height'] = self::FALLBACK_HEIGHT;
+			}
+			$node->parentNode->setAttribute( 'style', 'position:relative; width: 100%; height: ' . $new_attributes['height'] . 'px;' );
+			unset( $new_attributes['width'] );
+			unset( $new_attributes['height'] );
+		} elseif ( 'responsive' === $layout ) {
+			$node->parentNode->setAttribute( 'style', 'position:relative; width: 100%; height: auto' );
+		} elseif ( 'fixed' === $layout ) {
+			if ( ! isset( $new_attributes['height'] ) ) {
+				$new_attributes['height'] = self::FALLBACK_HEIGHT;
+			}
+		}
+
+		return $new_attributes;
+	}
+
+	/**
+	 * Add <amp-image-lightbox> element to body tag if it doesn't exist yet.
+	 */
+	public function maybe_add_amp_image_lightbox_node() {
+
+		$nodes = $this->dom->getElementById( self::AMP_IMAGE_LIGHTBOX_ID );
+		if ( null !== $nodes ) {
+			return;
+		}
+
+		$nodes = $this->dom->getElementsByTagName( 'body' );
+		if ( ! $nodes->length ) {
+			return;
+		}
+		$body_node          = $nodes->item( 0 );
+		$amp_image_lightbox = AMP_DOM_Utils::create_node( $this->dom, 'amp-image-lightbox', array(
+			'id'                           => self::AMP_IMAGE_LIGHTBOX_ID,
+			'layout'                       => 'nodisplay',
+			'data-close-button-aria-label' => __( 'Close', 'amp' ),
+		) );
+		$body_node->appendChild( $amp_image_lightbox );
+	}
+}
diff --git a/includes/sanitizers/class-amp-blacklist-sanitizer.php b/includes/sanitizers/class-amp-blacklist-sanitizer.php
new file mode 100644
index 00000000000..1b2eb9a9872
--- /dev/null
+++ b/includes/sanitizers/class-amp-blacklist-sanitizer.php
@@ -0,0 +1,301 @@
+<?php
+/**
+ * Class AMP_Blacklist_Sanitizer
+ *
+ * @package AMP
+ */
+
+/**
+ * Strips blacklisted tags and attributes from content.
+ *
+ * See following for blacklist:
+ *     https://github.com/ampproject/amphtml/blob/master/spec/amp-html-format.md#html-tags
+ *
+ * @since 0.5 This has been replaced by AMP_Tag_And_Attribute_Sanitizer but is kept around for back-compat.
+ * @deprecated
+ */
+class AMP_Blacklist_Sanitizer extends AMP_Base_Sanitizer {
+	const PATTERN_REL_WP_ATTACHMENT = '#wp-att-([\d]+)#';
+
+	/**
+	 * Default args.
+	 *
+	 * @var array
+	 */
+	protected $DEFAULT_ARGS = array(
+		'add_blacklisted_protocols' => array(),
+		'add_blacklisted_tags' => array(),
+		'add_blacklisted_attributes' => array(),
+	);
+
+	/**
+	 * Sanitize.
+	 */
+	public function sanitize() {
+		_deprecated_function( __METHOD__, '0.7', 'AMP_Tag_And_Attribute_Sanitizer::sanitize' );
+
+		$blacklisted_tags       = $this->get_blacklisted_tags();
+		$blacklisted_attributes = $this->get_blacklisted_attributes();
+		$blacklisted_protocols  = $this->get_blacklisted_protocols();
+
+		$body = $this->root_element;
+		$this->strip_tags( $body, $blacklisted_tags );
+		$this->strip_attributes_recursive( $body, $blacklisted_attributes, $blacklisted_protocols );
+	}
+
+	/**
+	 * Strip attributes recursively.
+	 *
+	 * @param DOMNode $node DOM Node.
+	 * @param array   $bad_attributes Bad attributes.
+	 * @param array   $bad_protocols  Bad protocols.
+	 */
+	private function strip_attributes_recursive( $node, $bad_attributes, $bad_protocols ) {
+		if ( XML_ELEMENT_NODE !== $node->nodeType ) {
+			return;
+		}
+
+		$node_name = $node->nodeName;
+
+		// Some nodes may contain valid content but are themselves invalid.
+		// Remove the node but preserve the children.
+		if ( 'font' === $node_name ) {
+			$this->replace_node_with_children( $node, $bad_attributes, $bad_protocols );
+			return;
+		} elseif ( 'a' === $node_name && false === $this->validate_a_node( $node ) ) {
+			$this->replace_node_with_children( $node, $bad_attributes, $bad_protocols );
+			return;
+		}
+
+		if ( $node->hasAttributes() ) {
+			$length = $node->attributes->length;
+			for ( $i = $length - 1; $i >= 0; $i-- ) {
+				$attribute      = $node->attributes->item( $i );
+				$attribute_name = strtolower( $attribute->name );
+				if ( in_array( $attribute_name, $bad_attributes, true ) ) {
+					$this->remove_invalid_attribute( $node, $attribute_name );
+					continue;
+				}
+
+				// The on* attributes (like onclick) are a special case.
+				if ( 0 === stripos( $attribute_name, 'on' ) && 'on' !== $attribute_name ) {
+					$this->remove_invalid_attribute( $node, $attribute_name );
+					continue;
+				} elseif ( 'a' === $node_name ) {
+					$this->sanitize_a_attribute( $node, $attribute );
+				}
+			}
+		}
+
+		$length = $node->childNodes->length;
+		for ( $i = $length - 1; $i >= 0; $i-- ) {
+			$child_node = $node->childNodes->item( $i );
+
+			$this->strip_attributes_recursive( $child_node, $bad_attributes, $bad_protocols );
+		}
+	}
+
+	/**
+	 * Strip tags.
+	 *
+	 * @param DOMElement $node      Node.
+	 * @param string[]   $tag_names Tag names.
+	 */
+	private function strip_tags( $node, $tag_names ) {
+		foreach ( $tag_names as $tag_name ) {
+			$elements = $node->getElementsByTagName( $tag_name );
+			$length   = $elements->length;
+			if ( 0 === $length ) {
+				continue;
+			}
+
+			for ( $i = $length - 1; $i >= 0; $i-- ) {
+				$element     = $elements->item( $i );
+				$parent_node = $element->parentNode;
+				$this->remove_invalid_child( $element );
+
+				if ( 'body' !== $parent_node->nodeName && AMP_DOM_Utils::is_node_empty( $parent_node ) ) {
+					$this->remove_invalid_child( $parent_node );
+				}
+			}
+		}
+	}
+
+	/**
+	 * Sanitize attribute.
+	 *
+	 * @param DOMElement $node      Node.
+	 * @param DOMAttr    $attribute Attribute.
+	 */
+	private function sanitize_a_attribute( $node, $attribute ) {
+		$attribute_name = strtolower( $attribute->name );
+
+		if ( 'rel' === $attribute_name ) {
+			$old_value = $attribute->value;
+			$new_value = trim( preg_replace( self::PATTERN_REL_WP_ATTACHMENT, '', $old_value ) );
+			if ( empty( $new_value ) ) {
+				$this->remove_invalid_attribute( $node, $attribute_name );
+			} elseif ( $old_value !== $new_value ) {
+				$node->setAttribute( $attribute_name, $new_value );
+			}
+		} elseif ( 'rev' === $attribute_name ) {
+			// rev removed from HTML5 spec, which was used by Jetpack Markdown.
+			$this->remove_invalid_attribute( $node, $attribute_name );
+		} elseif ( 'target' === $attribute_name ) {
+			// _blank is the only allowed value and it must be lowercase.
+			// replace _new with _blank and others should simply be removed.
+			$old_value = strtolower( $attribute->value );
+			if ( '_blank' === $old_value || '_new' === $old_value ) {
+				// _new is not allowed; swap with _blank
+				$node->setAttribute( $attribute_name, '_blank' );
+			} else {
+				// Only _blank is allowed.
+				$this->remove_invalid_attribute( $node, $attribute_name );
+			}
+		}
+	}
+
+	/**
+	 * Validate node.
+	 *
+	 * @param DOMElement $node Node.
+	 * @return bool
+	 */
+	private function validate_a_node( $node ) {
+		// Get the href attribute.
+		$href = $node->getAttribute( 'href' );
+
+		if ( empty( $href ) ) {
+			/*
+			 * If no href, check that a is an anchor or not.
+			 * We don't need to validate anchors any further.
+			 */
+			return $node->hasAttribute( 'name' ) || $node->hasAttribute( 'id' );
+		}
+
+		// If this is an anchor link, just return true.
+		if ( 0 === strpos( $href, '#' ) ) {
+			return true;
+		}
+
+		// If the href starts with a '/', append the home_url to it for validation purposes.
+		if ( 0 === stripos( $href, '/' ) ) {
+			$href = untrailingslashit( get_home_url() ) . $href;
+		}
+
+		$valid_protocols   = array( 'http', 'https', 'mailto', 'sms', 'tel', 'viber', 'whatsapp' );
+		$special_protocols = array( 'tel', 'sms' ); // These ones don't valid with `filter_var+FILTER_VALIDATE_URL`.
+		$protocol          = strtok( $href, ':' );
+
+		if ( false === filter_var( $href, FILTER_VALIDATE_URL )
+			&& ! in_array( $protocol, $special_protocols, true ) ) {
+			return false;
+		}
+
+		if ( ! in_array( $protocol, $valid_protocols, true ) ) {
+			return false;
+		}
+
+		return true;
+	}
+
+	/**
+	 * Replace node with children.
+	 *
+	 * @param DOMElement $node           Node.
+	 * @param array      $bad_attributes Bad attributes.
+	 * @param array      $bad_protocols  Bad protocols.
+	 */
+	private function replace_node_with_children( $node, $bad_attributes, $bad_protocols ) {
+		// If the node has children and also has a parent node,
+		// clone and re-add all the children just before current node.
+		if ( $node->hasChildNodes() && $node->parentNode ) {
+			foreach ( $node->childNodes as $child_node ) {
+				$new_child = $child_node->cloneNode( true );
+				$this->strip_attributes_recursive( $new_child, $bad_attributes, $bad_protocols );
+				$node->parentNode->insertBefore( $new_child, $node );
+			}
+		}
+
+		// Remove the node from the parent, if defined.
+		if ( $node->parentNode ) {
+			$this->remove_invalid_child( $node );
+		}
+	}
+
+	/**
+	 * Merge defaults with args.
+	 *
+	 * @param string $key    Key.
+	 * @param array  $values Values.
+	 * @return array Merged args.
+	 */
+	private function merge_defaults_with_args( $key, $values ) {
+		// Merge default values with user specified args.
+		if ( ! empty( $this->args[ $key ] )
+			&& is_array( $this->args[ $key ] ) ) {
+			$values = array_merge( $values, $this->args[ $key ] );
+		}
+
+		return $values;
+	}
+
+	/**
+	 * Get blacklisted protocols.
+	 *
+	 * @return array Protocols.
+	 */
+	private function get_blacklisted_protocols() {
+		return $this->merge_defaults_with_args( 'add_blacklisted_protocols', array(
+			'javascript',
+		) );
+	}
+
+	/**
+	 * Get blacklisted tags.
+	 *
+	 * @return array Tags.
+	 */
+	private function get_blacklisted_tags() {
+		return $this->merge_defaults_with_args( 'add_blacklisted_tags', array(
+			'script',
+			'noscript',
+			'style',
+			'frame',
+			'frameset',
+			'object',
+			'param',
+			'applet',
+			'form',
+			'label',
+			'input',
+			'textarea',
+			'select',
+			'option',
+			'link',
+			'picture',
+
+			// Sanitizers run after embed handlers, so if anything wasn't matched, it needs to be removed.
+			'embed',
+			'embedvideo',
+
+			// Other weird ones.
+			'comments-count',
+		) );
+	}
+
+	/**
+	 * Get blacklisted attributes.
+	 *
+	 * @return array Attributes.
+	 */
+	private function get_blacklisted_attributes() {
+		return $this->merge_defaults_with_args( 'add_blacklisted_attributes', array(
+			'style',
+			'size',
+			'clear',
+			'align',
+			'valign',
+		) );
+	}
+}
diff --git a/includes/sanitizers/class-amp-block-sanitizer.php b/includes/sanitizers/class-amp-block-sanitizer.php
new file mode 100644
index 00000000000..1cf0c0eff89
--- /dev/null
+++ b/includes/sanitizers/class-amp-block-sanitizer.php
@@ -0,0 +1,133 @@
+<?php
+/**
+ * Class AMP_Block_Sanitizer.
+ *
+ * @package AMP
+ */
+
+/**
+ * Class AMP_Block_Sanitizer
+ *
+ * Modifies elements created as blocks to match the blocks' AMP-specific configuration.
+ */
+class AMP_Block_Sanitizer extends AMP_Base_Sanitizer {
+
+	/**
+	 * Tag.
+	 *
+	 * @var string Figure tag to identify wrapper around AMP elements.
+	 * @since 1.0
+	 */
+	public static $tag = 'figure';
+
+	/**
+	 * Sanitize the AMP elements contained by <figure> element where necessary.
+	 *
+	 * @since 0.2
+	 */
+	public function sanitize() {
+		$nodes     = $this->dom->getElementsByTagName( self::$tag );
+		$num_nodes = $nodes->length;
+		if ( 0 === $num_nodes ) {
+			return;
+		}
+
+		for ( $i = $num_nodes - 1; $i >= 0; $i-- ) {
+			$node = $nodes->item( $i );
+
+			// We're looking for <figure> elements that have one child node only.
+			if ( 1 !== count( $node->childNodes ) ) {
+				continue;
+			}
+
+			$attributes = AMP_DOM_Utils::get_node_attributes_as_assoc_array( $node );
+
+			// We are only looking for <figure> elements which have wp-block-embed as class.
+			if ( ! isset( $attributes['class'] ) || false === strpos( $attributes['class'], 'wp-block-embed' ) ) {
+				continue;
+			}
+
+			// We are looking for <figure> elements with layout attribute only.
+			if (
+				! isset( $attributes['data-amp-layout'] ) &&
+				! isset( $attributes['data-amp-noloading'] ) &&
+				! isset( $attributes['data-amp-lightbox'] )
+			) {
+				continue;
+			}
+
+			$amp_el_found = false;
+
+			foreach ( $node->childNodes as $child_node ) {
+
+				// We are looking for child elements which start with 'amp-'.
+				if ( 0 !== strpos( $child_node->tagName, 'amp-' ) ) {
+					continue;
+				}
+				$amp_el_found = true;
+
+				$this->set_attributes( $child_node, $node, $attributes );
+			}
+
+			if ( false === $amp_el_found ) {
+				continue;
+			}
+			$this->did_convert_elements = true;
+		}
+	}
+
+	/**
+	 * Sets necessary attributes to both parent and AMP element node.
+	 *
+	 * @param DOMNode $node AMP element node.
+	 * @param DOMNode $parent_node <figure> node.
+	 * @param array   $attributes Current attributes of the AMP element.
+	 */
+	protected function set_attributes( $node, $parent_node, $attributes ) {
+
+		if ( isset( $attributes['data-amp-layout'] ) ) {
+			$node->setAttribute( 'layout', $attributes['data-amp-layout'] );
+		}
+		if ( isset( $attributes['data-amp-noloading'] ) && true === filter_var( $attributes['data-amp-noloading'], FILTER_VALIDATE_BOOLEAN ) ) {
+			$node->setAttribute( 'noloading', '' );
+		}
+
+		$layout = $node->getAttribute( 'layout' );
+
+		// The width has to be unset / auto in case of fixed-height.
+		if ( 'fixed-height' === $layout ) {
+			if ( ! isset( $attributes['height'] ) ) {
+				$node->setAttribute( 'height', self::FALLBACK_HEIGHT );
+			}
+			$node->setAttribute( 'width', 'auto' );
+
+			$height = $node->getAttribute( 'height' );
+			if ( is_numeric( $height ) ) {
+				$height .= 'px';
+			}
+			$parent_node->setAttribute( 'style', "height: $height; width: auto;" );
+
+			// The parent element should have width/height set and position set in case of 'fill'.
+		} elseif ( 'fill' === $layout ) {
+			if ( ! isset( $attributes['height'] ) ) {
+				$attributes['height'] = self::FALLBACK_HEIGHT;
+			}
+			$parent_node->setAttribute( 'style', 'position:relative; width: 100%; height: ' . $attributes['height'] . 'px;' );
+			$node->removeAttribute( 'width' );
+			$node->removeAttribute( 'height' );
+		} elseif ( 'responsive' === $layout ) {
+			$parent_node->setAttribute( 'style', 'position:relative; width: 100%; height: auto' );
+		} elseif ( 'fixed' === $layout ) {
+			if ( ! isset( $attributes['height'] ) ) {
+				$node->setAttribute( 'height', self::FALLBACK_HEIGHT );
+			}
+		}
+
+		// Set the fallback layout in case needed.
+		$attributes = AMP_DOM_Utils::get_node_attributes_as_assoc_array( $node );
+		$attributes = $this->set_layout( $attributes );
+		if ( $layout !== $attributes['layout'] ) {
+			$node->setAttribute( 'layout', $attributes['layout'] );
+		}
+	}
+}
diff --git a/includes/sanitizers/class-amp-comments-sanitizer.php b/includes/sanitizers/class-amp-comments-sanitizer.php
new file mode 100644
index 00000000000..05b3844723b
--- /dev/null
+++ b/includes/sanitizers/class-amp-comments-sanitizer.php
@@ -0,0 +1,156 @@
+<?php
+/**
+ * Class AMP_Comments_Sanitizer.
+ *
+ * @package AMP
+ */
+
+/**
+ * Class AMP_Comments_Sanitizer
+ *
+ * Strips and corrects attributes in forms.
+ */
+class AMP_Comments_Sanitizer extends AMP_Base_Sanitizer {
+
+	/**
+	 * Pre-process the comment form and comment list for AMP.
+	 *
+	 * @since 0.7
+	 */
+	public function sanitize() {
+
+		foreach ( $this->dom->getElementsByTagName( 'form' ) as $comment_form ) {
+			/**
+			 * Comment form.
+			 *
+			 * @var DOMElement $comment_form
+			 */
+			$action = $comment_form->getAttribute( 'action-xhr' );
+			if ( ! $action ) {
+				$action = $comment_form->getAttribute( 'action' );
+			}
+			$action_path = wp_parse_url( $action, PHP_URL_PATH );
+			if ( preg_match( '#/wp-comments-post\.php$#', $action_path ) ) {
+				$this->process_comment_form( $comment_form );
+			}
+		}
+	}
+
+	/**
+	 * Comment form.
+	 *
+	 * @param DOMElement $comment_form Comment form.
+	 */
+	protected function process_comment_form( $comment_form ) {
+		/**
+		 * Element.
+		 *
+		 * @var DOMElement $element
+		 */
+
+		/**
+		 * Named input elements.
+		 *
+		 * @var DOMElement[][] $form_fields
+		 */
+		$form_fields = array();
+		foreach ( $comment_form->getElementsByTagName( 'input' ) as $element ) {
+			$name = $element->getAttribute( 'name' );
+			if ( $name ) {
+				$form_fields[ $name ][] = $element;
+			}
+		}
+		foreach ( $comment_form->getElementsByTagName( 'textarea' ) as $element ) {
+			$name = $element->getAttribute( 'name' );
+			if ( $name ) {
+				$form_fields[ $name ][] = $element;
+			}
+		}
+
+		if ( empty( $form_fields['comment_post_ID'] ) ) {
+			return;
+		}
+		$post_id  = (int) $form_fields['comment_post_ID'][0]->getAttribute( 'value' );
+		$state_id = AMP_Theme_Support::get_comment_form_state_id( $post_id );
+
+		$form_state = array(
+			'values'      => array(),
+			'submitting'  => false,
+			'replyToName' => '',
+		);
+
+		if ( ! empty( $form_fields['comment_parent'] ) ) {
+			$comment_id = (int) $form_fields['comment_parent'][0]->getAttribute( 'value' );
+			if ( $comment_id ) {
+				$reply_comment = get_comment( $comment_id );
+				if ( $reply_comment ) {
+					$form_state['replyToName'] = $reply_comment->comment_author;
+				}
+			}
+		}
+
+		$amp_bind_attr_format = AMP_DOM_Utils::get_amp_bind_placeholder_prefix() . '%s';
+		foreach ( $form_fields as $name => $form_field ) {
+			foreach ( $form_field as $element ) {
+
+				// @todo Radio and checkbox inputs are not supported yet.
+				if ( in_array( strtolower( $element->getAttribute( 'type' ) ), array( 'checkbox', 'radio' ), true ) ) {
+					continue;
+				}
+
+				$element->setAttribute( sprintf( $amp_bind_attr_format, 'disabled' ), "$state_id.submitting" );
+
+				if ( 'textarea' === strtolower( $element->nodeName ) ) {
+					$form_state['values'][ $name ] = $element->textContent;
+					$element->setAttribute( sprintf( $amp_bind_attr_format, 'text' ), "$state_id.values.$name" );
+				} else {
+					$form_state['values'][ $name ] = $element->hasAttribute( 'value' ) ? $element->getAttribute( 'value' ) : '';
+					$element->setAttribute( sprintf( $amp_bind_attr_format, 'value' ), "$state_id.values.$name" );
+				}
+
+				// Update the state in response to changing the input.
+				$element->setAttribute( 'on', sprintf(
+					'change:AMP.setState( { %s: { values: { %s: event.value } } } )',
+					$state_id,
+					wp_json_encode( $name )
+				) );
+			}
+		}
+
+		// Add amp-state to the document.
+		$amp_state = $this->dom->createElement( 'amp-state' );
+		$amp_state->setAttribute( 'id', $state_id );
+		$script = $this->dom->createElement( 'script' );
+		$script->setAttribute( 'type', 'application/json' );
+		$amp_state->appendChild( $script );
+		$script->appendChild( $this->dom->createTextNode( wp_json_encode( $form_state ) ) );
+		$comment_form->insertBefore( $amp_state, $comment_form->firstChild );
+
+		// Update state when submitting form.
+		$form_reset_state = $form_state;
+		unset(
+			$form_reset_state['values']['author'],
+			$form_reset_state['values']['email'],
+			$form_reset_state['values']['url']
+		);
+		$on = array(
+			// Disable the form when submitting.
+			sprintf(
+				'submit:AMP.setState( { %s: { submitting: true } } )',
+				wp_json_encode( $state_id )
+			),
+			// Re-enable the form fields when the submission fails.
+			sprintf(
+				'submit-error:AMP.setState( { %s: { submitting: false } } )',
+				wp_json_encode( $state_id )
+			),
+			// Reset the form to its initial state (with enabled form fields), except for the author, email, and url.
+			sprintf(
+				'submit-success:AMP.setState( { %s: %s } )',
+				$state_id,
+				wp_json_encode( $form_reset_state )
+			),
+		);
+		$comment_form->setAttribute( 'on', implode( ';', $on ) );
+	}
+}
diff --git a/includes/sanitizers/class-amp-core-theme-sanitizer.php b/includes/sanitizers/class-amp-core-theme-sanitizer.php
new file mode 100644
index 00000000000..2e22faf4882
--- /dev/null
+++ b/includes/sanitizers/class-amp-core-theme-sanitizer.php
@@ -0,0 +1,1107 @@
+<?php
+/**
+ * Class AMP_Core_Theme_Sanitizer.
+ *
+ * @package AMP
+ * @since 1.0
+ */
+
+/**
+ * Class AMP_Core_Theme_Sanitizer
+ *
+ * Fixes up common issues in core themes and others.
+ *
+ * @see AMP_Validation_Error_Taxonomy::accept_core_theme_validation_errors()
+ * @since 1.0
+ */
+class AMP_Core_Theme_Sanitizer extends AMP_Base_Sanitizer {
+
+	/**
+	 * Array of flags used to control sanitization.
+	 *
+	 * @since 1.0
+	 * @var array {
+	 *      @type string $stylesheet     Stylesheet slug.
+	 *      @type string $template       Template slug.
+	 *      @type array  $theme_features List of theme features that need to be applied. Features are method names,
+	 * }
+	 */
+	protected $args;
+
+	/**
+	 * Body element.
+	 *
+	 * @since 1.0
+	 * @var DOMElement
+	 */
+	protected $body;
+
+	/**
+	 * XPath.
+	 *
+	 * @since 1.0
+	 * @var DOMXPath
+	 */
+	protected $xpath;
+
+	/**
+	 * Config for features needed by themes.
+	 *
+	 * @since 1.0
+	 * @var array
+	 */
+	protected static $theme_features = array(
+		// Twenty Nineteen.
+		'twentynineteen'  => array(
+			'dequeue_scripts'                             => array(
+				'twentynineteen-skip-link-focus-fix', // This is part of AMP. See <https://github.com/ampproject/amphtml/issues/18671>.
+				'twentynineteen-priority-menu',
+				'twentynineteen-touch-navigation', // @todo There could be an AMP implementation of this, similar to what is implemented on ampproject.org.
+			),
+			'remove_actions'                              => array(
+				'wp_print_footer_scripts' => array(
+					'twentynineteen_skip_link_focus_fix', // See <https://github.com/WordPress/twentynineteen/pull/47>.
+				),
+			),
+			'add_twentynineteen_masthead_styles'          => array(),
+			'add_twentynineteen_image_styles'             => array(),
+			'remove_twentynineteen_thumbnail_image_sizes' => array(),
+
+		),
+
+		// Twenty Seventeen.
+		'twentyseventeen' => array(
+			// @todo Try to implement belowEntryMetaClass().
+			'dequeue_scripts'                     => array(
+				'twentyseventeen-html5', // Only relevant for IE<9.
+				'twentyseventeen-global', // There are somethings not yet implemented in AMP. See todos below.
+				'jquery-scrollto', // Implemented via add_smooth_scrolling().
+				'twentyseventeen-navigation', // Handled by add_nav_menu_styles, add_nav_menu_toggle, add_nav_sub_menu_buttons.
+				'twentyseventeen-skip-link-focus-fix', // Only needed by IE11 and when admin bar is present.
+			),
+			'remove_actions'                      => array(
+				'wp_head' => array(
+					'twentyseventeen_javascript_detection', // AMP is essentially no-js, with any interactively added explicitly via amp-bind.
+				),
+			),
+			'force_svg_support'                   => array(),
+			'force_fixed_background_support'      => array(),
+			'add_twentyseventeen_masthead_styles' => array(),
+			'add_twentyseventeen_sticky_nav_menu' => array(),
+			'add_has_header_video_body_class'     => array(),
+			'add_nav_menu_styles'                 => array(),
+			'add_nav_menu_toggle'                 => array(),
+			'add_nav_sub_menu_buttons'            => array(),
+			'add_smooth_scrolling'                => array(
+				'//header[@id = "masthead"]//a[ contains( @class, "menu-scroll-down" ) ]',
+			),
+			'set_twentyseventeen_quotes_icon'     => array(),
+			'add_twentyseventeen_attachment_image_attributes' => array(),
+		),
+
+		// Twenty Sixteen.
+		'twentysixteen'   => array(
+			// @todo Figure out an AMP solution for onResizeARIA().
+			// @todo Try to implement belowEntryMetaClass().
+			'dequeue_scripts'          => array(
+				'twentysixteen-script',
+				'twentysixteen-html5', // Only relevant for IE<9.
+				'twentysixteen-keyboard-image-navigation', // AMP does not yet allow for listening to keydown events.
+				'twentysixteen-skip-link-focus-fix', // Only needed by IE11 and when admin bar is present.
+			),
+			'remove_actions'           => array(
+				'wp_head' => array(
+					'twentysixteen_javascript_detection', // AMP is essentially no-js, with any interactively added explicitly via amp-bind.
+				),
+			),
+			'add_nav_menu_styles'      => array(),
+			'add_nav_menu_toggle'      => array(),
+			'add_nav_sub_menu_buttons' => array(),
+		),
+
+		// Twenty Fifteen.
+		'twentyfifteen'   => array(
+			// @todo Figure out an AMP solution for onResizeARIA().
+			'dequeue_scripts'          => array(
+				'twentyfifteen-script',
+				'twentyfifteen-keyboard-image-navigation', // AMP does not yet allow for listening to keydown events.
+				'twentyfifteen-skip-link-focus-fix', // Only needed by IE11 and when admin bar is present.
+			),
+			'remove_actions'           => array(
+				'wp_head' => array(
+					'twentyfifteen_javascript_detection', // AMP is essentially no-js, with any interactively added explicitly via amp-bind.
+				),
+			),
+			'add_nav_menu_styles'      => array(),
+			'add_nav_menu_toggle'      => array(),
+			'add_nav_sub_menu_buttons' => array(),
+		),
+	);
+
+	/**
+	 * Get list of supported core themes.
+	 *
+	 * @since 1.0
+	 *
+	 * @return string[] Slugs for supported themes.
+	 */
+	public static function get_supported_themes() {
+		return array_keys( self::$theme_features );
+	}
+
+	/**
+	 * Get the acceptable validation errors.
+	 *
+	 * @since 1.0
+	 *
+	 * @param string $template Template.
+	 * @return array Acceptable errors.
+	 */
+	public static function get_acceptable_errors( $template ) {
+		switch ( $template ) {
+			case 'twentyfifteen':
+				return array(
+					'removed_unused_css_rules' => true,
+					'illegal_css_at_rule'      => array(
+						array(
+							'at_rule'         => 'viewport',
+							'node_attributes' => array(
+								'id' => 'twentyfifteen-style-css',
+							),
+						),
+						array(
+							'at_rule'         => '-ms-viewport',
+							'node_attributes' => array(
+								'id' => 'twentyfifteen-style-css',
+							),
+						),
+					),
+				);
+			case 'twentysixteen':
+				return array(
+					'removed_unused_css_rules' => true,
+					'illegal_css_at_rule'      => array(
+						array(
+							'at_rule'         => 'viewport',
+							'node_attributes' => array(
+								'id' => 'twentysixteen-style-css',
+							),
+						),
+						array(
+							'at_rule'         => '-ms-viewport',
+							'node_attributes' => array(
+								'id' => 'twentysixteen-style-css',
+							),
+						),
+					),
+				);
+			case 'twentyseventeen':
+				return array(
+					'removed_unused_css_rules' => true,
+				);
+		}
+		return array();
+	}
+
+	/**
+	 * Get theme config.
+	 *
+	 * @since 1.0
+	 *
+	 * @param string $theme Theme slug.
+	 * @return array Class names.
+	 */
+	protected static function get_theme_config( $theme ) {
+		// phpcs:disable WordPress.WP.I18n.TextDomainMismatch
+		$config = array(
+			'sub_menu_button_class' => 'dropdown-toggle',
+		);
+		switch ( $theme ) {
+			case 'twentyfifteen':
+				return array_merge(
+					$config,
+					array(
+						'nav_container_id'             => 'secondary',
+						'nav_container_toggle_class'   => 'toggled-on',
+						'menu_button_class'            => 'secondary-toggle',
+						'menu_button_xpath'            => '//header[ @id = "masthead" ]//button[ contains( @class, "secondary-toggle" ) ]',
+						'menu_button_toggle_class'     => 'toggled-on',
+						'sub_menu_button_toggle_class' => 'toggle-on',
+						'expand_text '                 => __( 'expand child menu', 'twentyfifteen' ),
+						'collapse_text'                => __( 'collapse child menu', 'twentyfifteen' ),
+					)
+				);
+
+			case 'twentysixteen':
+				return array_merge(
+					$config,
+					array(
+						'nav_container_id'             => 'site-header-menu',
+						'nav_container_toggle_class'   => 'toggled-on',
+						'menu_button_class'            => 'menu-toggle',
+						'menu_button_xpath'            => '//header[@id = "masthead"]//button[ @id = "menu-toggle" ]',
+						'menu_button_toggle_class'     => 'toggled-on',
+						'sub_menu_button_toggle_class' => 'toggled-on',
+						'expand_text '                 => __( 'expand child menu', 'twentysixteen' ),
+						'collapse_text'                => __( 'collapse child menu', 'twentysixteen' ),
+					)
+				);
+
+			case 'twentyseventeen':
+			default:
+				return array_merge(
+					$config,
+					array(
+						'nav_container_id'             => 'site-navigation',
+						'nav_container_toggle_class'   => 'toggled-on',
+						'menu_button_class'            => 'menu-toggle',
+						'menu_button_xpath'            => '//nav[@id = "site-navigation"]//button[ contains( @class, "menu-toggle" ) ]',
+						'menu_button_toggle_class'     => 'toggled-on',
+						'sub_menu_button_toggle_class' => 'toggled-on',
+						'expand_text '                 => __( 'expand child menu', 'twentyseventeen' ),
+						'collapse_text'                => __( 'collapse child menu', 'twentyseventeen' ),
+					)
+				);
+		}
+		// phpcs:enable WordPress.WP.I18n.TextDomainMismatch
+	}
+
+	/**
+	 * Find theme features for core theme.
+	 *
+	 * @since 1.0
+	 *
+	 * @param array $args   Args.
+	 * @param bool  $static Static. that is, whether should run during output buffering.
+	 * @return array Theme features.
+	 */
+	protected static function get_theme_features( $args, $static = false ) {
+		$theme_features   = array();
+		$theme_candidates = wp_array_slice_assoc( $args, array( 'stylesheet', 'template' ) );
+		foreach ( $theme_candidates as $theme_candidate ) {
+			if ( isset( self::$theme_features[ $theme_candidate ] ) ) {
+				$theme_features = self::$theme_features[ $theme_candidate ];
+				break;
+			}
+		}
+
+		// Allow specific theme features to be requested even if the theme is not in core.
+		if ( isset( $args['theme_features'] ) ) {
+			$theme_features = array_merge( $args['theme_features'], $theme_features );
+		}
+
+		$final_theme_features = array();
+		foreach ( $theme_features as $theme_feature => $feature_args ) {
+			if ( ! method_exists( __CLASS__, $theme_feature ) ) {
+				continue;
+			}
+			try {
+				$reflection = new ReflectionMethod( __CLASS__, $theme_feature );
+				if ( $reflection->isStatic() === $static ) {
+					$final_theme_features[ $theme_feature ] = $feature_args;
+				}
+			} catch ( Exception $e ) {
+				unset( $e );
+			}
+		}
+		return $final_theme_features;
+	}
+
+	/**
+	 * Add filters to manipulate output during output buffering before the DOM is constructed.
+	 *
+	 * @since 1.0
+	 *
+	 * @param array $args Args.
+	 */
+	public static function add_buffering_hooks( $args = array() ) {
+		$theme_features = self::get_theme_features( $args, true );
+		foreach ( $theme_features as $theme_feature => $feature_args ) {
+			if ( method_exists( __CLASS__, $theme_feature ) ) {
+				call_user_func( array( __CLASS__, $theme_feature ), $feature_args );
+			}
+		}
+	}
+
+	/**
+	 * Add filter to output the quote icons in front of the article content.
+	 *
+	 * This is only used in Twenty Seventeen.
+	 *
+	 * @since 1.0
+	 * @link https://github.com/WordPress/wordpress-develop/blob/f4580c122b7d0d2d66d22f806c6fe6e11023c6f0/src/wp-content/themes/twentyseventeen/assets/js/global.js#L105-L108
+	 */
+	public static function set_twentyseventeen_quotes_icon() {
+		add_filter( 'the_content', function ( $content ) {
+
+			// Why isn't Twenty Seventeen doing this to begin with? Why is it using JS to add the quote icon?
+			if ( function_exists( 'twentyseventeen_get_svg' ) && 'quote' === get_post_format() ) {
+				$icon    = twentyseventeen_get_svg( array( 'icon' => 'quote-right' ) );
+				$content = preg_replace( '#(<blockquote.*?>)#s', '$1' . $icon, $content );
+			}
+
+			return $content;
+		} );
+	}
+
+	/**
+	 * Remove the sizes attribute from thumbnail images in Twenty Nineteen.
+	 *
+	 * The AMP runtime sets an inline style on an <amp-img> based on the sizes attribute if it's present.
+	 * For example, <amp-img style="width:calc(50vw)">.
+	 * Removing the 'sizes' attribute isn't ideal, but it looks like it's not possible to override that inline style.
+	 *
+	 * @todo: remove when this is resolved: https://github.com/ampproject/amphtml/issues/17053
+	 * @since 1.0
+	 */
+	public static function remove_twentynineteen_thumbnail_image_sizes() {
+		add_filter( 'wp_get_attachment_image_attributes', function( $attr ) {
+			if ( isset( $attr['class'] ) && false !== strpos( $attr['class'], 'attachment-post-thumbnail' ) ) {
+				unset( $attr['sizes'] );
+			}
+
+			return $attr;
+		}, 11 );
+	}
+
+	/**
+	 * Add filter to adjust the attachment image attributes to ensure attachment pages have a consistent <amp-img> rendering.
+	 *
+	 * This is only used in Twenty Seventeen.
+	 *
+	 * @since 1.0
+	 * @link https://github.com/WordPress/wordpress-develop/blob/ddc8f803c6e99118998191fd2ea24124feb53659/src/wp-content/themes/twentyseventeen/functions.php#L545:L554
+	 */
+	public static function add_twentyseventeen_attachment_image_attributes() {
+		add_filter( 'wp_get_attachment_image_attributes', function ( $attr, $attachment, $size ) {
+			if ( isset( $attr['class'] ) && 'custom-logo' === $attr['class'] ) {
+				unset( $attr['sizes'] );
+			} elseif ( is_attachment() ) {
+				$sizes = wp_get_attachment_image_sizes( $attachment->ID, $size );
+				if ( false !== $sizes ) {
+					$attr['sizes'] = $sizes;
+				}
+			}
+			return $attr;
+		}, 11, 3 );
+
+		/*
+		 * The max-height of the `.custom-logo-link img` is defined as being 80px, unless
+		 * there is header media in which case it is 200px. Issues related to vertically-squashed
+		 * images can be avoided if we just make sure that the image has this height to begin with.
+		 */
+		add_filter( 'get_custom_logo', function( $html ) {
+			$src = wp_get_attachment_image_src( get_theme_mod( 'custom_logo' ), 'full' );
+			if ( ! $src ) {
+				return $html;
+			}
+
+			if ( 'blank' === get_header_textcolor() && has_custom_header() ) {
+				$height = 200;
+			} else {
+				$height = 80;
+			}
+			$width = $height * ( $src[1] / $src[2] ); // Note that float values are allowed.
+
+			$html = preg_replace( '/(?<=width=")\d+(?=")/', $width, $html );
+			$html = preg_replace( '/(?<=height=")\d+(?=")/', $height, $html );
+			return $html;
+		} );
+	}
+
+	/**
+	 * Fix up core themes to do things in the AMP way.
+	 *
+	 * @since 1.0
+	 */
+	public function sanitize() {
+		$this->body = $this->dom->getElementsByTagName( 'body' )->item( 0 );
+		if ( ! $this->body ) {
+			return;
+		}
+
+		$this->xpath = new DOMXPath( $this->dom );
+
+		$theme_features = self::get_theme_features( $this->args, false );
+		foreach ( $theme_features as $theme_feature => $feature_args ) {
+			if ( method_exists( $this, $theme_feature ) ) {
+				call_user_func( array( $this, $theme_feature ), $feature_args );
+			}
+		}
+	}
+
+	/**
+	 * Dequeue scripts.
+	 *
+	 * @since 1.0
+	 *
+	 * @param string[] $handles Handles, where each item value is the script handle.
+	 */
+	public static function dequeue_scripts( $handles = array() ) {
+		add_action( 'wp_enqueue_scripts', function() use ( $handles ) {
+			foreach ( $handles as $handle ) {
+				wp_dequeue_script( $handle );
+			}
+		}, PHP_INT_MAX );
+	}
+
+	/**
+	 * Remove actions.
+	 *
+	 * @since 1.0
+	 *
+	 * @param array $actions Actions, with action name as key and value being callback.
+	 */
+	public static function remove_actions( $actions = array() ) {
+		foreach ( $actions as $action => $callbacks ) {
+			foreach ( $callbacks as $callback ) {
+				$priority = has_action( $action, $callback );
+				if ( false !== $priority ) {
+					remove_action( $action, $callback, $priority );
+				}
+			}
+		}
+	}
+
+	/**
+	 * Add smooth scrolling from link to target element.
+	 *
+	 * @since 1.0
+	 *
+	 * @param string[] $link_xpaths XPath queries to the links that should smooth scroll.
+	 */
+	public function add_smooth_scrolling( $link_xpaths ) {
+		foreach ( $link_xpaths as $link_xpath ) {
+			foreach ( $this->xpath->query( $link_xpath ) as $link ) {
+				if ( $link instanceof DOMElement && preg_match( '/#(.+)/', $link->getAttribute( 'href' ), $matches ) ) {
+					$link->setAttribute( 'on', sprintf( 'tap:%s.scrollTo(duration=600)', $matches[1] ) );
+				}
+			}
+		}
+	}
+
+	/**
+	 * Force SVG support, replacing no-svg class name with svg class name.
+	 *
+	 * @since 1.0
+	 *
+	 * @link https://github.com/WordPress/wordpress-develop/blob/1af1f65a21a1a697fb5f33027497f9e5ae638453/src/wp-content/themes/twentyseventeen/assets/js/global.js#L211-L213
+	 * @link https://caniuse.com/#feat=svg
+	 */
+	public function force_svg_support() {
+		$this->dom->documentElement->setAttribute(
+			'class',
+			preg_replace(
+				'/(^|\s)no-svg(\s|$)/',
+				' svg ',
+				$this->dom->documentElement->getAttribute( 'class' )
+			)
+		);
+	}
+
+	/**
+	 * Force support for fixed background-attachment.
+	 *
+	 * @since 1.0
+	 *
+	 * @link https://github.com/WordPress/wordpress-develop/blob/1af1f65a21a1a697fb5f33027497f9e5ae638453/src/wp-content/themes/twentyseventeen/assets/js/global.js#L215-L217
+	 * @link https://caniuse.com/#feat=background-attachment
+	 */
+	public function force_fixed_background_support() {
+		$this->dom->documentElement->setAttribute(
+			'class',
+			$this->dom->documentElement->getAttribute( 'class' ) . ' background-fixed'
+		);
+	}
+
+	/**
+	 * Add body class when there is a header video.
+	 *
+	 * @since 1.0
+	 * @link https://github.com/WordPress/wordpress-develop/blob/a26c24226c6b131a0ed22c722a836c100d3ba254/src/wp-content/themes/twentyseventeen/assets/js/global.js#L244-L247
+	 *
+	 * @param array $args Args.
+	 */
+	public static function add_has_header_video_body_class( $args = array() ) {
+		$args = array_merge(
+			array(
+				'class_name' => 'has-header-video',
+			),
+			$args
+		);
+
+		add_filter( 'body_class', function( $body_classes ) use ( $args ) {
+			if ( has_header_video() ) {
+				$body_classes[] = $args['class_name'];
+			}
+			return $body_classes;
+		} );
+	}
+
+	/**
+	 * Get the (common) navigation outer height.
+	 *
+	 * @todo If the nav menu has many items and it spans multiple rows, this will be too small.
+	 * @link https://github.com/WordPress/wordpress-develop/blob/fd5ba80c5c3d9cf62348567073945e246285fbca/src/wp-content/themes/twentyseventeen/assets/js/global.js#L50
+	 *
+	 * @return int Navigation outer height.
+	 */
+	protected static function get_twentyseventeen_navigation_outer_height() {
+		return 72;
+	}
+
+	/**
+	 * Add required styles for featured image header in Twenty Nineteen.
+	 *
+	 * The following is necessary because the styles in the theme apply to the featured img,
+	 * and the CSS parser will then convert the selectors to amp-img. Nevertheless, object-fit
+	 * does not apply on amp-img and it needs to apply on an actual img.
+	 *
+	 * @link https://github.com/WordPress/wordpress-develop/blob/5.0/src/wp-content/themes/twentynineteen/style.css#L2276-L2299
+	 * @since 1.0
+	 */
+	public static function add_twentynineteen_masthead_styles() {
+		add_action( 'wp_enqueue_scripts', function() {
+			ob_start();
+			?>
+			<style>
+			.site-header.featured-image .site-featured-image .post-thumbnail amp-img > img {
+				height: auto;
+				left: 50%;
+				max-width: 1000%;
+				min-height: 100%;
+				min-width: 100vw;
+				position: absolute;
+				top: 50%;
+				transform: translateX(-50%) translateY(-50%);
+				width: auto;
+				z-index: 1;
+				/* When image filters are active, make it grayscale to colorize it blue. */
+			}
+
+			@supports (object-fit: cover) {
+				.site-header.featured-image .site-featured-image .post-thumbnail amp-img > img {
+					height: 100%;
+					left: 0;
+					object-fit: cover;
+					top: 0;
+					transform: none;
+					width: 100%;
+				}
+			}
+			</style>
+			<?php
+			$styles = str_replace( array( '<style>', '</style>' ), '', ob_get_clean() );
+			wp_add_inline_style( get_template() . '-style', $styles );
+		}, 11 );
+	}
+
+	/**
+	 * Add required styles for video and image headers.
+	 *
+	 * This is currently used exclusively for Twenty Seventeen.
+	 *
+	 * @since 1.0
+	 * @link https://github.com/WordPress/wordpress-develop/blob/1af1f65a21a1a697fb5f33027497f9e5ae638453/src/wp-content/themes/twentyseventeen/style.css#L1687
+	 * @link https://github.com/WordPress/wordpress-develop/blob/1af1f65a21a1a697fb5f33027497f9e5ae638453/src/wp-content/themes/twentyseventeen/style.css#L1743
+	 */
+	public static function add_twentyseventeen_masthead_styles() {
+		$args = self::get_theme_config( get_template() );
+
+		/*
+		 * The following is necessary because the styles in the theme apply to img and video,
+		 * and the CSS parser will then convert the selectors to amp-img and amp-video respectively.
+		 * Nevertheless, object-fit does not apply on amp-img and it needs to apply on an actual img.
+		 */
+		add_action( 'wp_enqueue_scripts', function() use ( $args ) {
+			$is_front_page_layout = ( is_front_page() && 'posts' !== get_option( 'show_on_front' ) ) || ( is_home() && is_front_page() );
+			ob_start();
+			?>
+			<style>
+				.has-header-image .custom-header-media amp-img > img,
+				.has-header-video .custom-header-media amp-video > video{
+					position: fixed;
+					height: auto;
+					left: 50%;
+					max-width: 1000%;
+					min-height: 100%;
+					min-width: 100%;
+					min-width: 100vw; /* vw prevents 1px gap on left that 100% has */
+					width: auto;
+					top: 50%;
+					padding-bottom: 1px; /* Prevent header from extending beyond the footer */
+					-ms-transform: translateX(-50%) translateY(-50%);
+					-moz-transform: translateX(-50%) translateY(-50%);
+					-webkit-transform: translateX(-50%) translateY(-50%);
+					transform: translateX(-50%) translateY(-50%);
+				}
+				.has-header-image:not(.twentyseventeen-front-page):not(.home) .custom-header-media amp-img > img {
+					bottom: 0;
+					position: absolute;
+					top: auto;
+					-ms-transform: translateX(-50%) translateY(0);
+					-moz-transform: translateX(-50%) translateY(0);
+					-webkit-transform: translateX(-50%) translateY(0);
+					transform: translateX(-50%) translateY(0);
+				}
+				/* For browsers that support object-fit */
+				@supports ( object-fit: cover ) {
+					.has-header-image .custom-header-media amp-img > img,
+					.has-header-video .custom-header-media amp-video > video,
+					.has-header-image:not(.twentyseventeen-front-page):not(.home) .custom-header-media amp-img > img {
+						height: 100%;
+						left: 0;
+						-o-object-fit: cover;
+						object-fit: cover;
+						top: 0;
+						-ms-transform: none;
+						-moz-transform: none;
+						-webkit-transform: none;
+						transform: none;
+						width: 100%;
+					}
+				}
+
+				.navigation-top.site-navigation-fixed {
+					display: none;
+				}
+
+				<?php if ( $is_front_page_layout && ! has_custom_header() ) : ?>
+					/* https://github.com/WordPress/wordpress-develop/blob/fd5ba80c5c3d9cf62348567073945e246285fbca/src/wp-content/themes/twentyseventeen/assets/js/global.js#L92-L94 */
+					.site-branding {
+						margin-bottom: <?php echo (int) AMP_Core_Theme_Sanitizer::get_twentyseventeen_navigation_outer_height(); ?>px;
+					}
+				<?php endif; ?>
+
+				@media screen and (min-width: 48em) {
+					/* Note that adjustHeaderHeight() is irrelevant with this change */
+					<?php if ( ! $is_front_page_layout ) : ?>
+						.navigation-top {
+							position: static;
+						}
+					<?php endif; ?>
+
+					/* Initial styles that amp-animations for navigationTopShow and navigationTopHide will override */
+					.navigation-top.site-navigation-fixed {
+						opacity: 0;
+						transform: translateY( -<?php echo (int) AMP_Core_Theme_Sanitizer::get_twentyseventeen_navigation_outer_height(); ?>px );
+						display: block;
+					}
+				}
+			</style>
+			<?php
+			$styles = str_replace( array( '<style>', '</style>' ), '', ob_get_clean() );
+			wp_add_inline_style( get_template() . '-style', $styles );
+		}, 11 );
+	}
+
+	/**
+	 * Add sticky nav menu to Twenty Seventeen.
+	 *
+	 * This is implemented by cloning the navigation-top element, giving it a fixed position outside of the viewport,
+	 * and then showing it at the top of the window as soon as the original nav begins to get scrolled out of view.
+	 * In order to improve accessibility, the cloned nav gets aria-hidden=true and all of the links get tabindex=-1
+	 * to prevent the keyboard from focusing on elements off the screen; it is not necessary to focus on the elements
+	 * in the fixed nav menu because as soon as the original nav menu is focused then the window is scrolled to the
+	 * top anyway.
+	 *
+	 * @since 1.0
+	 */
+	public function add_twentyseventeen_sticky_nav_menu() {
+		/**
+		 * Elements.
+		 *
+		 * @var DOMElement $link
+		 * @var DOMElement $navigation_top
+		 * @var DOMElement $navigation_top_fixed
+		 */
+		$navigation_top = $this->xpath->query( '//header[ @id = "masthead" ]//div[ contains( @class, "navigation-top" ) ]' )->item( 0 );
+		if ( ! $navigation_top ) {
+			return;
+		}
+
+		$navigation_top_fixed = $navigation_top->cloneNode( true );
+		$navigation_top_fixed->setAttribute( 'class', $navigation_top_fixed->getAttribute( 'class' ) . ' site-navigation-fixed' );
+
+		$navigation_top_fixed->setAttribute( 'aria-hidden', 'true' );
+		foreach ( $navigation_top_fixed->getElementsByTagName( 'a' ) as $link ) {
+			$link->setAttribute( 'tabindex', '-1' );
+		}
+
+		$navigation_top->parentNode->insertBefore( $navigation_top_fixed, $navigation_top->nextSibling );
+
+		$attributes = array(
+			'layout'              => 'nodisplay',
+			'intersection-ratios' => 1,
+			'on'                  => implode( ';', array(
+				'exit:navigationTopShow.start',
+				'enter:navigationTopHide.start',
+			) ),
+		);
+		if ( is_admin_bar_showing() ) {
+			$attributes['viewport-margins'] = '32px 0';
+		}
+		$position_observer = AMP_DOM_Utils::create_node( $this->dom, 'amp-position-observer', $attributes );
+		$navigation_top->appendChild( $position_observer );
+
+		$animations = array(
+			'navigationTopShow' => array(
+				'duration'   => 0,
+				'fill'       => 'both',
+				'animations' => array(
+					'selector'  => '.navigation-top.site-navigation-fixed',
+					'media'     => '(min-width: 48em)',
+					'keyframes' => array(
+						'opacity'   => 1.0,
+						'transform' => 'translateY( 0 )',
+					),
+				),
+			),
+			'navigationTopHide' => array(
+				'duration'   => 0,
+				'fill'       => 'both',
+				'animations' => array(
+					'selector'  => '.navigation-top.site-navigation-fixed',
+					'media'     => '(min-width: 48em)',
+					'keyframes' => array(
+						'opacity'   => 0.0,
+						'transform' => sprintf( 'translateY( -%dpx )', self::get_twentyseventeen_navigation_outer_height() ),
+					),
+				),
+			),
+		);
+
+		foreach ( $animations as $animation_id => $animation ) {
+			$amp_animation   = AMP_DOM_Utils::create_node( $this->dom, 'amp-animation', array(
+				'id'     => $animation_id,
+				'layout' => 'nodisplay',
+			) );
+			$position_script = $this->dom->createElement( 'script' );
+			$position_script->setAttribute( 'type', 'application/json' );
+			$position_script->appendChild( $this->dom->createTextNode( wp_json_encode( $animation ) ) );
+			$amp_animation->appendChild( $position_script );
+			$this->body->appendChild( $amp_animation );
+		}
+	}
+
+	/**
+	 * Add styles for the nav menu specifically to deal with AMP running in a no-js context.
+	 *
+	 * @since 1.0
+	 *
+	 * @param array $args Args.
+	 */
+	public static function add_nav_menu_styles( $args = array() ) {
+		$args = array_merge(
+			self::get_theme_config( get_template() ),
+			$args
+		);
+
+		add_action( 'wp_enqueue_scripts', function() use ( $args ) {
+			ob_start();
+			?>
+			<style>
+				/* Override no-js selector in parent theme. */
+				.no-js .main-navigation ul ul {
+					display: none;
+				}
+
+				/* Use sibling selector and re-use class on button instead of toggling toggle-on class on ul.sub-menu */
+				.main-navigation ul .<?php echo esc_html( $args['sub_menu_button_toggle_class'] ); ?> + .sub-menu {
+					display: block;
+				}
+
+				<?php if ( 'twentyseventeen' === get_template() ) : ?>
+					/* Show the button*/
+					.no-js .<?php echo esc_html( $args['menu_button_class'] ); ?> {
+						display: block;
+					}
+					.no-js .main-navigation > div > ul {
+						display: none;
+					}
+					.no-js .main-navigation.<?php echo esc_html( $args['nav_container_toggle_class'] ); ?> > div > ul {
+						display: block;
+					}
+					@media screen and (min-width: 48em) {
+						.no-js .<?php echo esc_html( $args['menu_button_class'] ); ?>,
+						.no-js .<?php echo esc_html( $args['sub_menu_button_class'] ); ?> {
+							display: none;
+						}
+						.no-js .main-navigation ul,
+						.no-js .main-navigation ul ul,
+						.no-js .main-navigation > div > ul {
+							display: block;
+						}
+						.main-navigation ul li.menu-item-has-children:focus-within:before,
+						.main-navigation ul li.menu-item-has-children:focus-within:after,
+						.main-navigation ul li.page_item_has_children:focus-within:before,
+						.main-navigation ul li.page_item_has_children:focus-within:after {
+							display: block;
+						}
+						.main-navigation ul ul li:focus-within > ul {
+							<?php if ( is_rtl() ) : ?>
+								left: auto;
+								right: 100%;
+							<?php else : ?>
+								left: 100%;
+								right: auto;
+							<?php endif; ?>
+						}
+						.main-navigation li li:focus-within {
+							background: #767676;
+						}
+						.main-navigation li li:focus-within > a,
+						.main-navigation li li a:focus-within,
+						.main-navigation li li.current_page_item a:focus-within,
+						.main-navigation li li.current-menu-item a:focus-within {
+							color: #fff;
+						}
+						.main-navigation ul li:focus-within > ul {
+							<?php if ( is_rtl() ) : ?>
+								left: auto;
+								right: 0.5em;
+							<?php else : ?>
+								left: 0.5em;
+								right: auto;
+							<?php endif; ?>
+						}
+
+						.main-navigation ul ul li.menu-item-has-children:focus-within:before,
+						.main-navigation ul ul li.menu-item-has-children:focus-within:after,
+						.main-navigation ul ul li.page_item_has_children:focus-within:before,
+						.main-navigation ul ul li.page_item_has_children:focus-within:after {
+							display: none;
+						}
+					}
+				<?php elseif ( 'twentysixteen' === get_template() ) : ?>
+					@media screen and (max-width: 56.875em) {
+						/* Show the button*/
+						.no-js .<?php echo esc_html( $args['menu_button_class'] ); ?> {
+							display: block;
+						}
+						.no-js .site-header-menu {
+							display: none;
+						}
+						.no-js .site-header-menu.toggled-on {
+							display: block;
+						}
+					}
+					@media screen and (min-width: 56.875em) {
+						.no-js .main-navigation ul ul {
+							display: block;
+						}
+						.main-navigation li:focus-within > a {
+							color: #007acc;
+						}
+						.main-navigation li:focus-within > ul {
+							<?php if ( is_rtl() ) : ?>
+								left: auto;
+								right: 0;
+							<?php else : ?>
+								left: 0;
+								right: auto;
+							<?php endif; ?>
+						}
+						.main-navigation ul ul li:focus-within > ul {
+							<?php if ( is_rtl() ) : ?>
+								left: 100%;
+								right: auto;
+							<?php else : ?>
+								left: auto;
+								right: 100%;
+							<?php endif; ?>
+						}
+					}
+				<?php elseif ( 'twentyfifteen' === get_template() ) : ?>
+					@media screen and (min-width: 59.6875em) {
+						/* Attempt to emulate https://github.com/WordPress/wordpress-develop/blob/5e9a39baa7d4368f7d3c36dcbcd53db6317677c9/src/wp-content/themes/twentyfifteen/js/functions.js#L108-L149 */
+						#sidebar {
+							position: sticky;
+							top: -9vh;
+							max-height: 109vh;
+							overflow-y: auto;
+						}
+					}
+
+				<?php endif; ?>
+			</style>
+			<?php
+			$styles = str_replace( array( '<style>', '</style>' ), '', ob_get_clean() );
+			wp_add_inline_style( get_template() . '-style', $styles );
+		}, 11 );
+	}
+
+	/**
+	 * Ensure that JS-only nav menu styles apply to AMP as well since even though scripts are not allowed, there are AMP-bind implementations.
+	 *
+	 * @since 1.0
+	 *
+	 * @param array $args Args.
+	 */
+	public function add_nav_menu_toggle( $args = array() ) {
+		$args = array_merge(
+			self::get_theme_config( get_template() ),
+			$args
+		);
+
+		$nav_el    = $this->dom->getElementById( $args['nav_container_id'] );
+		$button_el = $this->xpath->query( $args['menu_button_xpath'] )->item( 0 );
+		if ( ! $nav_el ) {
+			if ( $button_el ) {
+
+				// Remove the button since it won't be used.
+				$button_el->parentNode->removeChild( $button_el );
+			}
+			return;
+		}
+
+		if ( ! $button_el ) {
+			return;
+		}
+
+		$state_id = 'navMenuToggledOn';
+		$expanded = false;
+
+		$nav_el->setAttribute(
+			AMP_DOM_Utils::get_amp_bind_placeholder_prefix() . 'class',
+			sprintf(
+				"%s + ( $state_id ? %s : '' )",
+				wp_json_encode( $nav_el->getAttribute( 'class' ) ),
+				wp_json_encode( ' ' . $args['nav_container_toggle_class'] )
+			)
+		);
+
+		$state_el = $this->dom->createElement( 'amp-state' );
+		$state_el->setAttribute( 'id', $state_id );
+		$script_el = $this->dom->createElement( 'script' );
+		$script_el->setAttribute( 'type', 'application/json' );
+		$script_el->appendChild( $this->dom->createTextNode( wp_json_encode( $expanded ) ) );
+		$state_el->appendChild( $script_el );
+		$nav_el->parentNode->insertBefore( $state_el, $nav_el );
+
+		$button_on = sprintf( "tap:AMP.setState({ $state_id: ! $state_id })" );
+		$button_el->setAttribute( 'on', $button_on );
+		$button_el->setAttribute( 'aria-expanded', 'false' );
+		$button_el->setAttribute( AMP_DOM_Utils::get_amp_bind_placeholder_prefix() . 'aria-expanded', "$state_id ? 'true' : 'false'" );
+		$button_el->setAttribute(
+			AMP_DOM_Utils::get_amp_bind_placeholder_prefix() . 'class',
+			sprintf( "%s + ( $state_id ? %s : '' )", wp_json_encode( $button_el->getAttribute( 'class' ) ), wp_json_encode( ' ' . $args['menu_button_toggle_class'] ) )
+		);
+	}
+
+	/**
+	 * Add buttons for nav sub-menu items.
+	 *
+	 * @since 1.0
+	 * @link https://github.com/WordPress/wordpress-develop/blob/a26c24226c6b131a0ed22c722a836c100d3ba254/src/wp-content/themes/twentyseventeen/assets/js/navigation.js#L11-L43
+	 *
+	 * @param array $args Args.
+	 */
+	public static function add_nav_sub_menu_buttons( $args = array() ) {
+		$default_args = self::get_theme_config( get_template() );
+		switch ( get_template() ) {
+			case 'twentyseventeen':
+				if ( function_exists( 'twentyseventeen_get_svg' ) ) {
+					$default_args['icon'] = twentyseventeen_get_svg( array(
+						'icon'     => 'angle-down',
+						'fallback' => true,
+					) );
+				}
+				break;
+		}
+		$args = array_merge( $default_args, $args );
+
+		/**
+		 * Filter the HTML output of a nav menu item to add the AMP dropdown button to reveal the sub-menu.
+		 *
+		 * @see twentyfifteen_amp_setup_hooks()
+		 *
+		 * @param string $item_output Nav menu item HTML.
+		 * @param object $item        Nav menu item.
+		 * @return string Modified nav menu item HTML.
+		 */
+		add_filter( 'walker_nav_menu_start_el', function( $item_output, $item, $depth, $nav_menu_args ) use ( $args ) {
+			unset( $depth );
+
+			// Skip adding buttons to nav menu widgets for now.
+			if ( empty( $nav_menu_args->theme_location ) ) {
+				return $item_output;
+			}
+
+			if ( ! in_array( 'menu-item-has-children', $item->classes, true ) ) {
+				return $item_output;
+			}
+			static $nav_menu_item_number = 0;
+			$nav_menu_item_number++;
+
+			$expanded = in_array( 'current-menu-ancestor', $item->classes, true );
+
+			$expanded_state_id = 'navMenuItemExpanded' . $nav_menu_item_number;
+
+			// Create new state for managing storing the whether the sub-menu is expanded.
+			$item_output .= sprintf(
+				'<amp-state id="%s"><script type="application/json">%s</script></amp-state>',
+				esc_attr( $expanded_state_id ),
+				wp_json_encode( $expanded )
+			);
+
+			$dropdown_button  = '<button';
+			$dropdown_button .= sprintf(
+				' class="%s" [class]="%s"',
+				esc_attr( $args['sub_menu_button_class'] . ( $expanded ? ' ' . $args['sub_menu_button_toggle_class'] : '' ) ),
+				esc_attr( sprintf( "%s + ( $expanded_state_id ? %s : '' )", wp_json_encode( $args['sub_menu_button_class'] ), wp_json_encode( ' ' . $args['sub_menu_button_toggle_class'] ) ) )
+			);
+			$dropdown_button .= sprintf(
+				' aria-expanded="%s" [aria-expanded]="%s"',
+				esc_attr( wp_json_encode( $expanded ) ),
+				esc_attr( "$expanded_state_id ? 'true' : 'false'" )
+			);
+			$dropdown_button .= sprintf(
+				' on="%s"',
+				esc_attr( "tap:AMP.setState( { $expanded_state_id: ! $expanded_state_id } )" )
+			);
+			$dropdown_button .= '>';
+
+			if ( isset( $args['icon'] ) ) {
+				$dropdown_button .= $args['icon'];
+			}
+			if ( isset( $args['expand_text'] ) && isset( $args['collapse_text'] ) ) {
+				$dropdown_button .= sprintf(
+					'<span class="screen-reader-text" [text]="%s">%s</span>',
+					esc_attr( sprintf( "$expanded_state_id ? %s : %s", wp_json_encode( $args['collapse_text'] ), wp_json_encode( $args['expand_text'] ) ) ),
+					esc_html( $expanded ? $args['collapse_text'] : $args['expand_text'] )
+				);
+			}
+
+			$dropdown_button .= '</button>';
+
+			$item_output .= $dropdown_button;
+			return $item_output;
+		}, 10, 4 );
+	}
+
+	/**
+	 * Output image styles for twentynineteen.
+	 *
+	 * When <img> tags have an 'aligncenter' class, AMP_Img_Sanitizer::handle_centering() wraps theme in <figure class="aligncenter">.
+	 * This ensures that the image inside it is centered.
+	 *
+	 * @since 1.0
+	 *
+	 * @param array $args Arguments.
+	 */
+	public static function add_twentynineteen_image_styles( $args = array() ) {
+		add_action( 'wp_enqueue_scripts', function() use ( $args ) {
+			ob_start();
+			?>
+			<style>
+				figure.aligncenter {
+					text-align: center
+				}
+			</style>
+			<?php
+			$styles = str_replace( array( '<style>', '</style>' ), '', ob_get_clean() );
+			wp_add_inline_style( get_template() . '-style', $styles );
+		}, 11 );
+	}
+}
diff --git a/includes/sanitizers/class-amp-embed-sanitizer.php b/includes/sanitizers/class-amp-embed-sanitizer.php
new file mode 100644
index 00000000000..6d32afd5b18
--- /dev/null
+++ b/includes/sanitizers/class-amp-embed-sanitizer.php
@@ -0,0 +1,47 @@
+<?php
+/**
+ * Class AMP_Embed_Sanitizer
+ *
+ * @package AMP
+ */
+
+/**
+ * Class AMP_Embed_Sanitizer
+ *
+ * Calls sanitize_raw_embeds method on embed handlers.
+ */
+class AMP_Embed_Sanitizer extends AMP_Base_Sanitizer {
+
+	/**
+	 * Embed handlers.
+	 *
+	 * @var AMP_Base_Embed_Handler[] AMP_Base_Embed_Handler[]
+	 */
+	private $embed_handlers = array();
+
+	/**
+	 * AMP_Embed_Sanitizer constructor.
+	 *
+	 * @param DOMDocument $dom  DOM.
+	 * @param array       $args Args.
+	 */
+	public function __construct( $dom, $args = array() ) {
+		parent::__construct( $dom, $args );
+
+		if ( ! empty( $this->args['embed_handlers'] ) ) {
+			$this->embed_handlers = $this->args['embed_handlers'];
+		}
+	}
+
+	/**
+	 * Checks if each embed_handler has sanitize_raw_method and calls it.
+	 */
+	public function sanitize() {
+
+		foreach ( $this->embed_handlers as $embed_handler ) {
+			if ( method_exists( $embed_handler, 'sanitize_raw_embeds' ) ) {
+				$embed_handler->sanitize_raw_embeds( $this->dom );
+			}
+		}
+	}
+}
diff --git a/includes/sanitizers/class-amp-form-sanitizer.php b/includes/sanitizers/class-amp-form-sanitizer.php
new file mode 100644
index 00000000000..03babed13c5
--- /dev/null
+++ b/includes/sanitizers/class-amp-form-sanitizer.php
@@ -0,0 +1,156 @@
+<?php
+/**
+ * Class AMP_Form_Sanitizer.
+ *
+ * @package AMP
+ * @since 0.7
+ */
+
+/**
+ * Class AMP_Form_Sanitizer
+ *
+ * Strips and corrects attributes in forms.
+ *
+ * @since 0.7
+ */
+class AMP_Form_Sanitizer extends AMP_Base_Sanitizer {
+
+	/**
+	 * Tag.
+	 *
+	 * @var string HTML <form> tag to identify and process.
+	 *
+	 * @since 0.7
+	 */
+	public static $tag = 'form';
+
+	/**
+	 * Get mapping of HTML selectors to the AMP component selectors which they may be converted into.
+	 *
+	 * @return array Mapping.
+	 */
+	public function get_selector_conversion_mapping() {
+		return array(
+			'form' => array( 'amp-form' ),
+		);
+	}
+
+	/**
+	 * Sanitize the <form> elements from the HTML contained in this instance's DOMDocument.
+	 *
+	 * @link https://www.ampproject.org/docs/reference/components/amp-form
+	 * @since 0.7
+	 */
+	public function sanitize() {
+
+		/**
+		 * Node list.
+		 *
+		 * @var DOMNodeList $node
+		 */
+		$nodes     = $this->dom->getElementsByTagName( self::$tag );
+		$num_nodes = $nodes->length;
+
+		if ( 0 === $num_nodes ) {
+			return;
+		}
+
+		for ( $i = $num_nodes - 1; $i >= 0; $i-- ) {
+			$node = $nodes->item( $i );
+			if ( ! $node instanceof DOMElement ) {
+				continue;
+			}
+
+			// In HTML, the default method is 'get'.
+			$method = 'get';
+			if ( $node->getAttribute( 'method' ) ) {
+				$method = strtolower( $node->getAttribute( 'method' ) );
+			} else {
+				$node->setAttribute( 'method', $method );
+			}
+
+			/*
+			 * In HTML, the default action is just the current URL that the page is served from.
+			 * The action "specifies a server endpoint to handle the form input. The value must be an
+			 * https URL and must not be a link to a CDN".
+			 */
+			if ( ! $node->getAttribute( 'action' ) ) {
+				$action_url = esc_url_raw( '//' . $_SERVER['HTTP_HOST'] . wp_unslash( $_SERVER['REQUEST_URI'] ) ); // WPCS: ignore. input var okay, sanitization ok.
+			} else {
+				$action_url = $node->getAttribute( 'action' );
+				// Check if action_url is a relative path and add the host to it.
+				if ( ! preg_match( '#^(https?:)?//#', $action_url ) ) {
+					$action_url = esc_url_raw( '//' . $_SERVER['HTTP_HOST'] . $action_url );
+				}
+			}
+			$xhr_action = $node->getAttribute( 'action-xhr' );
+
+			// Make HTTP URLs protocol-less, since HTTPS is required for forms.
+			if ( 'http://' === strtolower( substr( $action_url, 0, 7 ) ) ) {
+				$action_url = substr( $action_url, 5 );
+			}
+
+			/*
+			 * "For GET submissions, provide at least one of action or action-xhr".
+			 * "This attribute is required for method=GET. For method=POST, the
+			 * action attribute is invalid, use action-xhr instead".
+			 */
+			if ( 'get' === $method ) {
+				if ( $action_url !== $node->getAttribute( 'action' ) ) {
+					$node->setAttribute( 'action', $action_url );
+				}
+			} elseif ( 'post' === $method ) {
+				$node->removeAttribute( 'action' );
+				if ( ! $xhr_action ) {
+					// record that action was converted tp action-xhr.
+					$action_url = add_query_arg( '_wp_amp_action_xhr_converted', 1, $action_url );
+					$node->setAttribute( 'action-xhr', $action_url );
+					// Append error handler if not found.
+					$this->ensure_submit_error_element( $node );
+				} elseif ( 'http://' === substr( $xhr_action, 0, 7 ) ) {
+					$node->setAttribute( 'action-xhr', substr( $xhr_action, 5 ) );
+				}
+			}
+
+			/*
+			 * The target "indicates where to display the form response after submitting the form.
+			 * The value must be _blank or _top". The _self and _parent values are treated
+			 * as synonymous with _top, and anything else is treated like _blank.
+			 */
+			$target = $node->getAttribute( 'target' );
+			if ( '_top' !== $target ) {
+				if ( ! $target || in_array( $target, array( '_self', '_parent' ), true ) ) {
+					$node->setAttribute( 'target', '_top' );
+				} elseif ( '_blank' !== $target ) {
+					$node->setAttribute( 'target', '_blank' );
+				}
+			}
+		}
+	}
+
+	/**
+	 * Checks if the form has an error handler else create one if not.
+	 *
+	 * @link https://www.ampproject.org/docs/reference/components/amp-form#success/error-response-rendering
+	 * @since 0.7
+	 *
+	 * @param DOMElement $form The form node to check.
+	 */
+	public function ensure_submit_error_element( $form ) {
+		$templates = $form->getElementsByTagName( 'template' );
+		for ( $i = $templates->length - 1; $i >= 0; $i-- ) {
+			if ( $templates->item( $i )->parentNode->hasAttribute( 'submit-error' ) ) {
+				return; // Found error template, do nothing.
+			}
+		}
+
+		$div      = $this->dom->createElement( 'div' );
+		$template = $this->dom->createElement( 'template' );
+		$mustache = $this->dom->createTextNode( '{{{error}}}' );
+		$div->setAttribute( 'submit-error', '' );
+		$template->setAttribute( 'type', 'amp-mustache' );
+		$template->appendChild( $mustache );
+		$div->appendChild( $template );
+		$form->appendChild( $div );
+	}
+}
diff --git a/includes/sanitizers/class-amp-gallery-block-sanitizer.php b/includes/sanitizers/class-amp-gallery-block-sanitizer.php
new file mode 100644
index 00000000000..beda1cfb0c3
--- /dev/null
+++ b/includes/sanitizers/class-amp-gallery-block-sanitizer.php
@@ -0,0 +1,207 @@
+<?php
+/**
+ * Class AMP_Gallery_Block_Sanitizer.
+ *
+ * @package AMP
+ */
+
+/**
+ * Class AMP_Gallery_Block_Sanitizer
+ *
+ * Modifies gallery block to match the block's AMP-specific configuration.
+ */
+class AMP_Gallery_Block_Sanitizer extends AMP_Base_Sanitizer {
+
+	/**
+	 * Value used for width of amp-carousel.
+	 *
+	 * @since 1.0
+	 *
+	 * @const int
+	 */
+	const FALLBACK_WIDTH = 600;
+
+	/**
+	 * Value used for height of amp-carousel.
+	 *
+	 * @since 1.0
+	 *
+	 * @const int
+	 */
+	const FALLBACK_HEIGHT = 480;
+
+	/**
+	 * Tag.
+	 *
+	 * @since 1.0
+	 *
+	 * @var string Ul tag to identify wrapper around gallery block.
+	 */
+	public static $tag = 'ul';
+
+	/**
+	 * Expected class of the wrapper around the gallery block.
+	 *
+	 * @since 1.0
+	 *
+	 * @var string
+	 */
+	public static $class = 'wp-block-gallery';
+
+	/**
+	 * Array of flags used to control sanitization.
+	 *
+	 * @var array {
+	 *      @type int  $content_max_width Max width of content.
+	 *      @type bool $carousel_required Whether carousels are required. This is used when amp theme support is not present, for back-compat.
+	 * }
+	 */
+	protected $args;
+
+	/**
+	 * Default args.
+	 *
+	 * @var array
+	 */
+	protected $DEFAULT_ARGS = array(
+		'carousel_required' => false,
+	);
+
+	/**
+	 * Sanitize the gallery block contained by <ul> element where necessary.
+	 *
+	 * @since 0.2
+	 */
+	public function sanitize() {
+		$nodes     = $this->dom->getElementsByTagName( self::$tag );
+		$num_nodes = $nodes->length;
+		if ( 0 === $num_nodes ) {
+			return;
+		}
+
+		for ( $i = $num_nodes - 1; $i >= 0; $i-- ) {
+			$node = $nodes->item( $i );
+
+			// We're looking for <ul> elements that have at least one child and the proper class.
+			if ( 0 === count( $node->childNodes ) || false === strpos( $node->getAttribute( 'class' ), self::$class ) ) {
+				continue;
+			}
+
+			$attributes      = AMP_DOM_Utils::get_node_attributes_as_assoc_array( $node );
+			$is_amp_lightbox = isset( $attributes['data-amp-lightbox'] ) && true === filter_var( $attributes['data-amp-lightbox'], FILTER_VALIDATE_BOOLEAN );
+			$is_amp_carousel = ! empty( $this->args['carousel_required'] ) || ( isset( $attributes['data-amp-carousel'] ) && true === filter_var( $attributes['data-amp-carousel'], FILTER_VALIDATE_BOOLEAN ) );
+
+			// We are only looking for <ul> elements which have amp-carousel / amp-lightbox true.
+			if ( ! $is_amp_carousel && ! $is_amp_lightbox ) {
+				continue;
+			}
+
+			// If lightbox is set, we should add lightbox feature to the gallery images.
+			if ( $is_amp_lightbox ) {
+				$this->add_lightbox_attributes_to_image_nodes( $node );
+				$this->maybe_add_amp_image_lightbox_node();
+			}
+
+			// If amp-carousel is not set, nothing else to do here.
+			if ( ! $is_amp_carousel ) {
+				continue;
+			}
+
+			$images = array();
+
+			// If it's not AMP lightbox, look for links first.
+			if ( ! $is_amp_lightbox ) {
+				foreach ( $node->getElementsByTagName( 'a' ) as $element ) {
+					$images[] = $element;
+				}
+			}
+
+			// If not linking to anything then look for <amp-img>.
+			if ( empty( $images ) ) {
+				foreach ( $node->getElementsByTagName( 'amp-img' ) as $element ) {
+					$images[] = $element;
+				}
+			}
+
+			// Skip if no images found.
+			if ( empty( $images ) ) {
+				continue;
+			}
+
+			$amp_carousel = AMP_DOM_Utils::create_node( $this->dom, 'amp-carousel', array(
+				'height' => $this->get_carousel_height( $node ),
+				'type'   => 'slides',
+				'layout' => 'fixed-height',
+			) );
+			foreach ( $images as $image ) {
+				$amp_carousel->appendChild( $image );
+			}
+
+			$node->parentNode->replaceChild( $amp_carousel, $node );
+		}
+		$this->did_convert_elements = true;
+	}
+
+	/**
+	 * Get carousel height by containing images.
+	 *
+	 * @param DOMElement $element The UL element.
+	 * @return int Height.
+	 */
+	protected function get_carousel_height( $element ) {
+		$images     = $element->getElementsByTagName( 'amp-img' );
+		$num_images = $images->length;
+		$max_height = 0;
+		$max_width  = 0;
+		if ( 0 === $num_images ) {
+			return self::FALLBACK_HEIGHT;
+		}
+		foreach ( $images as $image ) {
+			/**
+			 * Image.
+			 *
+			 * @var DOMElement $image
+			 */
+			$image_height = $image->getAttribute( 'height' );
+			if ( is_numeric( $image_height ) ) {
+				$max_height = max( $max_height, $image_height );
+			}
+			$image_width = $image->getAttribute( 'height' );
+			if ( is_numeric( $image_width ) ) {
+				$max_width = max( $max_width, $image_width );
+			}
+		}
+
+		if ( ! empty( $this->args['content_max_width'] ) && $max_height > 0 && $max_width > $this->args['content_max_width'] ) {
+			$max_height = ( $max_width * $this->args['content_max_width'] ) / $max_height;
+		}
+
+		return ! $max_height ? self::FALLBACK_HEIGHT : $max_height;
+	}
+
+	/**
+	 * Set lightbox related attributes to <amp-img> within gallery.
+	 *
+	 * @param DOMElement $element The UL element.
+	 */
+	protected function add_lightbox_attributes_to_image_nodes( $element ) {
+		$images     = $element->getElementsByTagName( 'amp-img' );
+		$num_images = $images->length;
+		if ( 0 === $num_images ) {
+			return;
+		}
+		$attributes = array(
+			'data-amp-lightbox' => '',
+			'on'                => 'tap:' . self::AMP_IMAGE_LIGHTBOX_ID,
+			'role'              => 'button',
+			'tabindex'          => 0,
+		);
+
+		for ( $j = $num_images - 1; $j >= 0; $j-- ) {
+			$image_node = $images->item( $j );
+			foreach ( $attributes as $att => $value ) {
+				$image_node->setAttribute( $att, $value );
+			}
+		}
+	}
+}
diff --git a/includes/sanitizers/class-amp-iframe-sanitizer.php b/includes/sanitizers/class-amp-iframe-sanitizer.php
new file mode 100644
index 00000000000..267992104bd
--- /dev/null
+++ b/includes/sanitizers/class-amp-iframe-sanitizer.php
@@ -0,0 +1,196 @@
+<?php
+/**
+ * Class AMP_Iframe_Sanitizer
+ *
+ * @package AMP
+ */
+
+/**
+ * Class AMP_Iframe_Sanitizer
+ *
+ * Converts <iframe> tags to <amp-iframe>
+ */
+class AMP_Iframe_Sanitizer extends AMP_Base_Sanitizer {
+
+	/**
+	 * Value used for height attribute when $attributes['height'] is empty.
+	 *
+	 * @since 0.2
+	 *
+	 * @const int
+	 */
+	const FALLBACK_HEIGHT = 400;
+
+	/**
+	 * Default values for sandboxing IFrame.
+	 *
+	 * @since 0.2
+	 *
+	 * @const int
+	 */
+	const SANDBOX_DEFAULTS = 'allow-scripts allow-same-origin';
+
+	/**
+	 * Tag.
+	 *
+	 * @var string HTML <iframe> tag to identify and replace with AMP version.
+	 *
+	 * @since 0.2
+	 */
+	public static $tag = 'iframe';
+
+	/**
+	 * Default args.
+	 *
+	 * @var array
+	 */
+	protected $DEFAULT_ARGS = array(
+		'add_placeholder' => false,
+	);
+
+	/**
+	 * Get mapping of HTML selectors to the AMP component selectors which they may be converted into.
+	 *
+	 * @return array Mapping.
+	 */
+	public function get_selector_conversion_mapping() {
+		return array(
+			'iframe' => array(
+				'amp-iframe',
+			),
+		);
+	}
+
+	/**
+	 * Sanitize the <iframe> elements from the HTML contained in this instance's DOMDocument.
+	 *
+	 * @since 0.2
+	 */
+	public function sanitize() {
+		$nodes     = $this->dom->getElementsByTagName( self::$tag );
+		$num_nodes = $nodes->length;
+		if ( 0 === $num_nodes ) {
+			return;
+		}
+
+		for ( $i = $num_nodes - 1; $i >= 0; $i-- ) {
+			$node           = $nodes->item( $i );
+			$normalized_attributes = $this->normalize_attributes( AMP_DOM_Utils::get_node_attributes_as_assoc_array( $node ) );
+
+			/**
+			 * If the src doesn't exist, remove the node. Either it never
+			 * existed or was invalidated while filtering attributes above.
+			 *
+			 * @todo: add a filter to allow for a fallback element in this instance.
+			 * @see: https://github.com/ampproject/amphtml/issues/2261
+			 */
+			if ( empty( $normalized_attributes['src'] ) ) {
+				$this->remove_invalid_child( $node );
+				continue;
+			}
+
+			$this->did_convert_elements = true;
+			$normalized_attributes      = $this->set_layout( $normalized_attributes );
+			if ( empty( $normalized_attributes['layout'] ) && ! empty( $normalized_attributes['width'] ) && ! empty( $normalized_attributes['height'] ) ) {
+				$normalized_attributes['layout'] = 'intrinsic';
+				$this->add_or_append_attribute( $normalized_attributes, 'class', 'amp-wp-enforced-sizes' );
+			}
+
+			$new_node = AMP_DOM_Utils::create_node( $this->dom, 'amp-iframe', $normalized_attributes );
+
+			if ( true === $this->args['add_placeholder'] ) {
+				$placeholder_node = $this->build_placeholder( $normalized_attributes );
+				$new_node->appendChild( $placeholder_node );
+			}
+
+			$node->parentNode->replaceChild( $new_node, $node );
+		}
+	}
+
+	/**
+	 * Normalize HTML attributes for <amp-iframe> elements.
+	 *
+	 *
+	 * @param string[] $attributes {
+	 *      Attributes.
+	 *
+	 *      @type string $src IFrame URL - Empty if HTTPS required per $this->args['require_https_src']
+	 *      @type int $width <iframe> width attribute - Set to numeric value if px or %
+	 *      @type int $height <iframe> width attribute - Set to numeric value if px or %
+	 *      @type string $sandbox <iframe> `sandbox` attribute - Pass along if found; default to value of self::SANDBOX_DEFAULTS
+	 *      @type string $class <iframe> `class` attribute - Pass along if found
+	 *      @type string $sizes <iframe> `sizes` attribute - Pass along if found
+	 *      @type string $id <iframe> `id` attribute - Pass along if found
+	 *      @type int $frameborder <iframe> `frameborder` attribute - Filter to '0' or '1'; default to '0'
+	 *      @type bool $allowfullscreen <iframe> `allowfullscreen` attribute - Convert 'false' to empty string ''
+	 *      @type bool $allowtransparency <iframe> `allowtransparency` attribute - Convert 'false' to empty string ''
+	 * }
+	 * @return array Returns HTML attributes; normalizes src, dimensions, frameborder, sandox, allowtransparency and allowfullscreen
+	 */
+	private function normalize_attributes( $attributes ) {
+		$out = array();
+
+		foreach ( $attributes as $name => $value ) {
+			switch ( $name ) {
+				case 'src':
+					$out[ $name ] = $this->maybe_enforce_https_src( $value, true );
+					break;
+
+				case 'width':
+				case 'height':
+					$out[ $name ] = $this->sanitize_dimension( $value, $name );
+					break;
+
+				case 'frameborder':
+					if ( '0' !== $value && '1' !== $value ) {
+						$value = '0';
+					}
+					$out[ $name ] = $value;
+					break;
+
+				case 'allowfullscreen':
+				case 'allowtransparency':
+					if ( 'false' !== $value ) {
+						$out[ $name ] = '';
+					}
+					break;
+
+				default:
+					$out[ $name ] = $value;
+					break;
+			}
+		}
+
+		if ( ! isset( $out['sandbox'] ) ) {
+			$out['sandbox'] = self::SANDBOX_DEFAULTS;
+		}
+
+		return $out;
+	}
+
+	/**
+	 * Builds a DOMElement to use as a placeholder for an <iframe>.
+	 *
+	 * Important: The element returned must not be block-level (e.g. div) as the PHP DOM parser
+	 * will move it out from inside any containing paragraph. So this is why a span is used.
+	 *
+	 * @since 0.2
+	 *
+	 * @param string[] $parent_attributes {
+	 *      Attributes.
+	 *
+	 *      @type string $placeholder AMP HTML <amp-iframe> `placeholder` attribute; default to 'amp-wp-iframe-placeholder'
+	 *      @type string $class AMP HTML <amp-iframe> `class` attribute; default to 'amp-wp-iframe-placeholder'
+	 * }
+	 * @return DOMElement|false
+	 */
+	private function build_placeholder( $parent_attributes ) {
+		$placeholder_node = AMP_DOM_Utils::create_node( $this->dom, 'span', array(
+			'placeholder' => '',
+			'class'       => 'amp-wp-iframe-placeholder',
+		) );
+
+		return $placeholder_node;
+	}
+
+}
diff --git a/includes/sanitizers/class-amp-img-sanitizer.php b/includes/sanitizers/class-amp-img-sanitizer.php
new file mode 100644
index 00000000000..9252b7139f8
--- /dev/null
+++ b/includes/sanitizers/class-amp-img-sanitizer.php
@@ -0,0 +1,376 @@
+<?php
+/**
+ * Class AMP_Img_Sanitizer.
+ *
+ * @package AMP
+ */
+
+/**
+ * Class AMP_Img_Sanitizer
+ *
+ * Converts <img> tags to <amp-img> or <amp-anim>
+ */
+class AMP_Img_Sanitizer extends AMP_Base_Sanitizer {
+
+	/**
+	 * Value used for width attribute when $attributes['width'] is empty.
+	 *
+	 * @since 0.2
+	 *
+	 * @const int
+	 */
+	const FALLBACK_WIDTH = 600;
+
+	/**
+	 * Value used for height attribute when $attributes['height'] is empty.
+	 *
+	 * @since 0.2
+	 *
+	 * @const int
+	 */
+	const FALLBACK_HEIGHT = 400;
+
+	/**
+	 * Tag.
+	 *
+	 * @var string HTML <img> tag to identify and replace with AMP version.
+	 *
+	 * @since 0.2
+	 */
+	public static $tag = 'img';
+
+	/**
+	 * Animation extension.
+	 *
+	 * @var string
+	 */
+	private static $anim_extension = '.gif';
+
+	/**
+	 * Get mapping of HTML selectors to the AMP component selectors which they may be converted into.
+	 *
+	 * @return array Mapping.
+	 */
+	public function get_selector_conversion_mapping() {
+		return array(
+			'img' => array(
+				'amp-img',
+				'amp-anim',
+			),
+		);
+	}
+
+	/**
+	 * Sanitize the <img> elements from the HTML contained in this instance's DOMDocument.
+	 *
+	 * @since 0.2
+	 */
+	public function sanitize() {
+
+		/**
+		 * Node list.
+		 *
+		 * @var DOMNodeList $node
+		 */
+		$nodes           = $this->dom->getElementsByTagName( self::$tag );
+		$need_dimensions = array();
+
+		$num_nodes = $nodes->length;
+
+		if ( 0 === $num_nodes ) {
+			return;
+		}
+
+		for ( $i = $num_nodes - 1; $i >= 0; $i-- ) {
+			$node = $nodes->item( $i );
+			if ( ! $node instanceof DOMElement ) {
+				continue;
+			}
+
+			if ( ! $node->hasAttribute( 'src' ) || '' === trim( $node->getAttribute( 'src' ) ) ) {
+				$this->remove_invalid_child( $node );
+				continue;
+			}
+
+			// Determine which images need their dimensions determined/extracted.
+			if ( ! is_numeric( $node->getAttribute( 'width' ) ) || ! is_numeric( $node->getAttribute( 'height' ) ) ) {
+				$need_dimensions[ $node->getAttribute( 'src' ) ][] = $node;
+			} else {
+				$this->adjust_and_replace_node( $node );
+			}
+		}
+
+		$this->determine_dimensions( $need_dimensions );
+		$this->adjust_and_replace_nodes_in_array_map( $need_dimensions );
+	}
+
+	/**
+	 * "Filter" HTML attributes for <amp-anim> elements.
+	 *
+	 * @since 0.2
+	 *
+	 * @param string[] $attributes {
+	 *      Attributes.
+	 *
+	 *      @type string $src Image URL - Pass along if found
+	 *      @type string $alt <img> `alt` attribute - Pass along if found
+	 *      @type string $class <img> `class` attribute - Pass along if found
+	 *      @type string $srcset <img> `srcset` attribute - Pass along if found
+	 *      @type string $sizes <img> `sizes` attribute - Pass along if found
+	 *      @type string $on <img> `on` attribute - Pass along if found
+	 *      @type string $attribution <img> `attribution` attribute - Pass along if found
+	 *      @type int $width <img> width attribute - Set to numeric value if px or %
+	 *      @type int $height <img> width attribute - Set to numeric value if px or %
+	 * }
+	 * @return array Returns HTML attributes; removes any not specifically declared above from input.
+	 */
+	private function filter_attributes( $attributes ) {
+		$out = array();
+
+		foreach ( $attributes as $name => $value ) {
+			switch ( $name ) {
+				case 'width':
+				case 'height':
+					$out[ $name ] = $this->sanitize_dimension( $value, $name );
+					break;
+
+				case 'data-amp-layout':
+					$out['layout'] = $value;
+					break;
+
+				case 'data-amp-noloading':
+					$out['noloading'] = $value;
+					break;
+
+				default:
+					$out[ $name ] = $value;
+					break;
+			}
+		}
+
+		return $out;
+	}
+
+	/**
+	 * Determine width and height attribute values for images without them.
+	 *
+	 * Attempt to determine actual dimensions, otherwise set reasonable defaults.
+	 *
+	 * @param DOMElement[][] $need_dimensions Map <img> @src URLs to node for images with missing dimensions.
+	 */
+	private function determine_dimensions( $need_dimensions ) {
+
+		$dimensions_by_url = AMP_Image_Dimension_Extractor::extract( array_keys( $need_dimensions ) );
+
+		foreach ( $dimensions_by_url as $url => $dimensions ) {
+			foreach ( $need_dimensions[ $url ] as $node ) {
+				if ( ! $node instanceof DOMElement ) {
+					continue;
+				}
+				$class = $node->getAttribute( 'class' );
+				if ( ! $class ) {
+					$class = '';
+				}
+				if ( ! $dimensions ) {
+					$class .= ' amp-wp-unknown-size';
+				}
+
+				$width  = isset( $this->args['content_max_width'] ) ? $this->args['content_max_width'] : self::FALLBACK_WIDTH;
+				$height = self::FALLBACK_HEIGHT;
+				if ( isset( $dimensions['width'] ) ) {
+					$width = $dimensions['width'];
+				}
+				if ( isset( $dimensions['height'] ) ) {
+					$height = $dimensions['height'];
+				}
+
+				if ( ! is_numeric( $node->getAttribute( 'width' ) ) ) {
+
+					// Let width have the right aspect ratio based on the height attribute.
+					if ( is_numeric( $node->getAttribute( 'height' ) ) && isset( $dimensions['height'] ) && isset( $dimensions['width'] ) ) {
+						$width = ( floatval( $node->getAttribute( 'height' ) ) * $dimensions['width'] ) / $dimensions['height'];
+					}
+
+					$node->setAttribute( 'width', $width );
+					if ( ! isset( $dimensions['width'] ) ) {
+						$class .= ' amp-wp-unknown-width';
+					}
+				}
+				if ( ! is_numeric( $node->getAttribute( 'height' ) ) ) {
+
+					// Let height have the right aspect ratio based on the width attribute.
+					if ( is_numeric( $node->getAttribute( 'width' ) ) && isset( $dimensions['width'] ) && isset( $dimensions['height'] ) ) {
+						$height = ( floatval( $node->getAttribute( 'width' ) ) * $dimensions['height'] ) / $dimensions['width'];
+					}
+
+					$node->setAttribute( 'height', $height );
+					if ( ! isset( $dimensions['height'] ) ) {
+						$class .= ' amp-wp-unknown-height';
+					}
+				}
+				$node->setAttribute( 'class', trim( $class ) );
+			}
+		}
+	}
+
+	/**
+	 * Now that all images have width and height attributes, make final tweaks and replace original image nodes
+	 *
+	 * @param DOMNodeList[] $node_lists Img DOM nodes (now with width and height attributes).
+	 */
+	private function adjust_and_replace_nodes_in_array_map( $node_lists ) {
+		foreach ( $node_lists as $node_list ) {
+			foreach ( $node_list as $node ) {
+				$this->adjust_and_replace_node( $node );
+			}
+		}
+	}
+
+	/**
+	 * Make final modifications to DOMNode
+	 *
+	 * @param DOMElement $node The DOMNode to adjust and replace.
+	 */
+	private function adjust_and_replace_node( $node ) {
+
+		$amp_data       = $this->get_data_amp_attributes( $node );
+		$old_attributes = AMP_DOM_Utils::get_node_attributes_as_assoc_array( $node );
+		$old_attributes = $this->filter_data_amp_attributes( $old_attributes, $amp_data );
+		$old_attributes = $this->maybe_add_lightbox_attributes( $old_attributes, $node );
+
+		$new_attributes = $this->filter_attributes( $old_attributes );
+		$layout         = isset( $amp_data['layout'] ) ? $amp_data['layout'] : false;
+		$new_attributes = $this->filter_attachment_layout_attributes( $node, $new_attributes, $layout );
+
+		$this->add_or_append_attribute( $new_attributes, 'class', 'amp-wp-enforced-sizes' );
+		if ( empty( $new_attributes['layout'] ) && ! empty( $new_attributes['height'] ) && ! empty( $new_attributes['width'] ) ) {
+			$new_attributes['layout'] = 'intrinsic';
+		}
+
+		if ( $this->is_gif_url( $new_attributes['src'] ) ) {
+			$this->did_convert_elements = true;
+
+			$new_tag = 'amp-anim';
+		} else {
+			$new_tag = 'amp-img';
+		}
+		$new_node = AMP_DOM_Utils::create_node( $this->dom, $new_tag, $new_attributes );
+		$new_node = $this->handle_centering( $new_node );
+		$node->parentNode->replaceChild( $new_node, $node );
+		$this->add_auto_width_to_figure( $new_node );
+	}
+
+	/**
+	 * Set lightbox attributes.
+	 *
+	 * @param array   $attributes Array of attributes.
+	 * @param DomNode $node Array of AMP attributes.
+	 * @return array Updated attributes.
+	 */
+	private function maybe_add_lightbox_attributes( $attributes, $node ) {
+		$parent_node = $node->parentNode;
+		if ( ! ( $parent_node instanceof DOMElement ) || 'figure' !== $parent_node->tagName ) {
+			return $attributes;
+		}
+
+		$parent_attributes = AMP_DOM_Utils::get_node_attributes_as_assoc_array( $parent_node );
+
+		if ( isset( $parent_attributes['data-amp-lightbox'] ) && true === filter_var( $parent_attributes['data-amp-lightbox'], FILTER_VALIDATE_BOOLEAN ) ) {
+			$attributes['data-amp-lightbox'] = '';
+			$attributes['on']                = 'tap:' . self::AMP_IMAGE_LIGHTBOX_ID;
+			$attributes['role']              = 'button';
+			$attributes['tabindex']          = 0;
+
+			$this->maybe_add_amp_image_lightbox_node();
+		}
+
+		return $attributes;
+	}
+
+	/**
+	 * Determines is a URL is considered a GIF URL
+	 *
+	 * @since 0.2
+	 *
+	 * @param string $url URL to inspect for GIF vs. JPEG or PNG.
+	 *
+	 * @return bool Returns true if $url ends in `.gif`
+	 */
+	private function is_gif_url( $url ) {
+		$ext  = self::$anim_extension;
+		$path = wp_parse_url( $url, PHP_URL_PATH );
+		return substr( $path, -strlen( $ext ) ) === $ext;
+	}
+
+	/**
+	 * Handles an issue with the aligncenter class.
+	 *
+	 * If the <amp-img> has the class aligncenter, this strips the class and wraps it in a <figure> to center the image.
+	 * There was an issue where the aligncenter class overrode the "display: inline-block" rule of AMP's layout="intrinsic" attribute.
+	 * So this strips that class, and instead wraps the image in a <figure> to center it.
+	 *
+	 * @since 0.7
+	 * @see https://github.com/Automattic/amp-wp/issues/1104
+	 *
+	 * @param DOMElement $node The <amp-img> node.
+	 * @return DOMElement $node The <amp-img> node, possibly wrapped in a <figure>.
+	 */
+	public function handle_centering( $node ) {
+		$align_class = 'aligncenter';
+		$classes     = $node->getAttribute( 'class' );
+		$width       = $node->getAttribute( 'width' );
+
+		// If this doesn't have a width attribute, centering it in the <figure> wrapper won't work.
+		if ( empty( $width ) || ! in_array( $align_class, preg_split( '/\s+/', trim( $classes ) ), true ) ) {
+			return $node;
+		}
+
+		// Strip the class, and wrap the <amp-img> in a <figure>.
+		$classes = trim( str_replace( $align_class, '', $classes ) );
+		$node->setAttribute( 'class', $classes );
+		$figure = AMP_DOM_Utils::create_node(
+			$this->dom,
+			'figure',
+			array(
+				'class' => $align_class,
+				'style' => "max-width: {$width}px;",
+			)
+		);
+		$figure->appendChild( $node );
+
+		return $figure;
+	}
+
+	/**
+	 * Add an inline style to set the `<figure>` element's width to `auto` instead of `fit-content`.
+	 *
+	 * @since 1.0
+	 * @see https://github.com/Automattic/amp-wp/issues/1086
+	 *
+	 * @param DOMElement $node The DOMNode to adjust and replace.
+	 */
+	protected function add_auto_width_to_figure( $node ) {
+		$figure = $node->parentNode;
+		if ( ! ( $figure instanceof DOMElement ) || 'figure' !== $figure->tagName ) {
+			return;
+		}
+
+		$class = $figure->getAttribute( 'class' );
+		// Target only the <figure> with a 'wp-block-image' class attribute.
+		if ( false === strpos( $class, 'wp-block-image' ) ) {
+			return;
+		}
+
+		// Target only <figure> without a 'is-resized' class attribute.
+		if ( false !== strpos( $class, 'is-resized' ) ) {
+			return;
+		}
+
+		$new_style = 'width: auto;';
+		if ( $figure->hasAttribute( 'style' ) ) {
+			$figure->setAttribute( 'style', $new_style . $figure->getAttribute( 'style' ) );
+		} else {
+			$figure->setAttribute( 'style', $new_style );
+		}
+	}
+}
diff --git a/includes/sanitizers/class-amp-o2-player-sanitizer.php b/includes/sanitizers/class-amp-o2-player-sanitizer.php
new file mode 100644
index 00000000000..0d594f8a7af
--- /dev/null
+++ b/includes/sanitizers/class-amp-o2-player-sanitizer.php
@@ -0,0 +1,140 @@
+<?php
+/**
+ * Class AMP_O2_Player_Sanitizer
+ *
+ * @package AMP
+ */
+
+/**
+ * Class AMP_O2_Player_Sanitizer
+ *
+ * Converts <div class="vdb_player><script></script></div> embed to <amp-o2-player>
+ *
+ * @since 1.0
+ * @see https://www.ampproject.org/docs/reference/components/amp-o2-player
+ */
+class AMP_O2_Player_Sanitizer extends AMP_Base_Sanitizer {
+	/**
+	 * Pattern to extract the information required for amp-o2-player element: data-pid, data-vid, data-bcid.
+	 *
+	 * @since 1.0
+	 */
+	const URL_PATTERN = '#.*delivery.vidible.tv\/jsonp\/pid=(?<data_pid>.*)\/vid=(?<data_vid>.*)\/(?<data_bcid>.*).js.*#i';
+
+	/**
+	 * AMP Tag.
+	 *
+	 * @since 1.0
+	 * @var string AMP Tag.
+	 */
+	private static $amp_tag = 'amp-o2-player';
+
+	/**
+	 * Amp O2 Player class.
+	 *
+	 * @since 1.0
+	 * @var string CSS class to identify O2 Player <div> to replace with AMP version.
+	 */
+	private static $xpath_selector = '//div[ contains( @class, \'vdb_player\' ) ]/script';
+
+	/**
+	 * Height to set for O2 Player elements.
+	 *
+	 * @since 1.0
+	 * @var string
+	 */
+	private static $height = '270';
+
+	/**
+	 * Width to set for O2 Player elements.
+	 *
+	 * @since 1.0
+	 * @var string
+	 */
+	private static $width = '480';
+
+	/**
+	 * Sanitize the O2 Player elements from the HTML contained in this instance's DOMDocument.
+	 *
+	 * @since 1.0
+	 */
+	public function sanitize() {
+		/**
+		 * XPath.
+		 *
+		 * @var DOMXPath $xpath
+		 */
+		$xpath = new DOMXPath( $this->dom );
+
+		/**
+		 * Node list.
+		 *
+		 * @var DOMNodeList $nodes
+		 */
+		$nodes     = $xpath->query( self::$xpath_selector );
+		$num_nodes = $nodes->length;
+
+		if ( 0 === $num_nodes ) {
+			return;
+		}
+
+		for ( $i = $num_nodes - 1; $i >= 0; $i-- ) {
+			$node = $nodes->item( $i );
+
+			$this->create_amp_o2_player( $this->dom, $node );
+		}
+
+	}
+
+	/**
+	 * Replaces node with amp-o2-player
+	 *
+	 * @since 1.0
+	 * @param DOMDocument $dom  The HTML Document.
+	 * @param DOMElement  $node The DOMNode to adjust and replace.
+	 */
+	private function create_amp_o2_player( $dom, $node ) {
+		$o2_attributes = $this->get_o2_player_attributes( $node->getAttribute( 'src' ) );
+
+		if ( ! empty( $o2_attributes ) ) {
+			$component_attributes = array_merge(
+				$o2_attributes, array(
+					'data-macros' => 'm.playback=click',
+					'layout'      => 'responsive',
+					'width'       => self::$width,
+					'height'      => self::$height,
+				)
+			);
+
+			$amp_o2_player = AMP_DOM_Utils::create_node( $dom, self::$amp_tag, $component_attributes );
+
+			$parent_node = $node->parentNode;
+
+			// replaces the wrapper that contains the script with amp-o2-player element.
+			$parent_node->parentNode->replaceChild( $amp_o2_player, $parent_node );
+
+			$this->did_convert_elements = true;
+		}
+	}
+
+	/**
+	 * Gets O2 Player's required attributes from script src
+	 *
+	 * @since 1.0
+	 * @param string $src Script src.
+	 *
+	 * @return array The data-* attributes for o2 player.
+	 */
+	private function get_o2_player_attributes( $src ) {
+		$found = preg_match( self::URL_PATTERN, $src, $matches );
+		if ( $found ) {
+			return array(
+				'data-pid'  => $matches['data_pid'],
+				'data-vid'  => $matches['data_vid'],
+				'data-bcid' => $matches['data_bcid'],
+			);
+		}
+		return array();
+	}
+
+}
diff --git a/includes/sanitizers/class-amp-playbuzz-sanitizer.php b/includes/sanitizers/class-amp-playbuzz-sanitizer.php
new file mode 100644
index 00000000000..3ec07e5f8b9
--- /dev/null
+++ b/includes/sanitizers/class-amp-playbuzz-sanitizer.php
@@ -0,0 +1,146 @@
+<?php
+/**
+ * Class AMP_Playbuzz_Sanitizer
+ *
+ * @package AMP
+ */
+
+/**
+ * Class AMP_Playbuzz_Sanitizer
+ *
+ * Converts Playbuzz embed to <amp-playbuzz>
+ *
+ * @see https://www.playbuzz.com/
+ */
+class AMP_Playbuzz_Sanitizer extends AMP_Base_Sanitizer {
+
+	/**
+	 * Tag.
+	 *
+	 * @var string HTML tag to identify and replace with AMP version.
+	 * @since 0.2
+	 */
+	public static $tag = 'div';
+
+	/**
+	 * PlayBuzz class.
+	 *
+	 * @var string CSS class to identify Playbuzz <div> to replace with AMP version.
+	 *
+	 * @since 0.2
+	 */
+	public static $pb_class = 'pb_feed';
+
+	/**
+	 * Hardcoded height to set for Playbuzz elements.
+	 *
+	 * @var string
+	 *
+	 * @since 0.2
+	 */
+	private static $height = '500';
+
+	/**
+	 * Get mapping of HTML selectors to the AMP component selectors which they may be converted into.
+	 *
+	 * @return array Mapping.
+	 */
+	public function get_selector_conversion_mapping() {
+		return array(
+			'div.pb_feed' => array( 'amp-playbuzz.pb_feed' ),
+		);
+	}
+
+	/**
+	 * Sanitize the Playbuzz elements from the HTML contained in this instance's DOMDocument.
+	 *
+	 * @since 0.2
+	 */
+	public function sanitize() {
+
+		$nodes     = $this->dom->getElementsByTagName( self::$tag );
+		$num_nodes = $nodes->length;
+
+		if ( 0 === $num_nodes ) {
+			return;
+		}
+
+		for ( $i = $num_nodes - 1; $i >= 0; $i-- ) {
+			$node = $nodes->item( $i );
+
+			if ( self::$pb_class !== $node->getAttribute( 'class' ) ) {
+				continue;
+			}
+
+			$old_attributes = AMP_DOM_Utils::get_node_attributes_as_assoc_array( $node );
+
+			$new_attributes = $this->filter_attributes( $old_attributes );
+
+			if ( ! isset( $new_attributes['data-item'] ) && ! isset( $new_attributes['src'] ) ) {
+				continue;
+			}
+
+			$new_node = AMP_DOM_Utils::create_node( $this->dom, 'amp-playbuzz', $new_attributes );
+
+			$node->parentNode->replaceChild( $new_node, $node );
+
+			$this->did_convert_elements = true;
+
+		}
+
+	}
+
+	/**
+	 * "Filter" HTML attributes for <amp-audio> elements.
+	 *
+	 * @since 0.2
+	 *
+	 * @param string[] $attributes {
+	 *      Attributes.
+	 *
+	 *      @type string $data-item Playbuzz <div> attribute - Pass along if found and not empty.
+	 *      @type string $data-game Playbuzz <div> attribute - Assign to its value to $attributes['src'] if found and not empty.
+	 *      @type string $data-game-info Playbuzz <div> attribute - Assign to its value to $attributes['data-item-info'] if found.
+	 *      @type string $data-shares Playbuzz <div> attribute - Assign to its value to $attributes['data-share-buttons'] if found.
+	 *      @type string $data-comments Playbuzz <div> attribute - Pass along if found.
+	 *      @type int $height Playbuzz <div> attribute - Set to hardcoded value of 500.
+	 * }
+	 * @return array Returns HTML attributes; removes any not specifically declared above from input.
+	 */
+	private function filter_attributes( $attributes ) {
+		$out = array();
+
+		foreach ( $attributes as $name => $value ) {
+			switch ( $name ) {
+				case 'data-item':
+					if ( ! empty( $value ) ) {
+						$out['data-item'] = $value;
+					}
+					break;
+
+				case 'data-game':
+					if ( ! empty( $value ) ) {
+						$out['src'] = $value;
+					}
+					break;
+
+				case 'data-shares':
+					$out['data-share-buttons'] = $value;
+					break;
+
+				case 'data-game-info':
+				case 'data-comments':
+				case 'class':
+					$out[ $name ] = $value;
+					break;
+
+				default:
+					break;
+			}
+		}
+
+		$out['height'] = self::$height;
+
+		return $out;
+	}
+}
diff --git a/includes/sanitizers/class-amp-rule-spec.php b/includes/sanitizers/class-amp-rule-spec.php
new file mode 100644
index 00000000000..a09fb94eb5b
--- /dev/null
+++ b/includes/sanitizers/class-amp-rule-spec.php
@@ -0,0 +1,139 @@
+<?php
+/**
+ * Class AMP_Rule_Spec
+ *
+ * @package AMP
+ */
+
+/**
+ * Class AMP_Rule_Spec
+ *
+ * Set of constants used throughout the sanitizer.
+ */
+abstract class AMP_Rule_Spec {
+
+	/**
+	 * AMP rule_spec types
+	 */
+	const ATTR_SPEC_LIST = 'attr_spec_list';
+	const TAG_SPEC       = 'tag_spec';
+	const CDATA          = 'cdata';
+
+	/**
+	 * AMP attr_spec value check results.
+	 *
+	 * In 0.7 these changed from strings to integers to speed up comparisons.
+	 */
+	const PASS           = 1;
+	const FAIL           = 0;
+	const NOT_APPLICABLE = -1;
+
+	/**
+	 * HTML Element Tag rule names
+	 */
+	const DISALLOWED_ANCESTOR = 'disallowed_ancestor';
+	const MANDATORY_ANCESTOR  = 'mandatory_ancestor';
+	const MANDATORY_PARENT    = 'mandatory_parent';
+
+	/**
+	 * HTML Element Attribute rule names
+	 */
+	const ALLOW_EMPTY             = 'allow_empty';
+	const ALLOW_RELATIVE          = 'allow_relative';
+	const ALLOWED_PROTOCOL        = 'protocol';
+	const ALTERNATIVE_NAMES       = 'alternative_names';
+	const BLACKLISTED_VALUE_REGEX = 'blacklisted_value_regex';
+	const DISALLOWED_DOMAIN       = 'disallowed_domain';
+	const MANDATORY               = 'mandatory';
+	const VALUE                   = 'value';
+	const VALUE_CASEI             = 'value_casei';
+	const VALUE_REGEX             = 'value_regex';
+	const VALUE_REGEX_CASEI       = 'value_regex_casei';
+	const VALUE_PROPERTIES        = 'value_properties';
+	const VALUE_URL               = 'value_url';
+
+	/**
+	 * Supported layout values.
+	 *
+	 * @since 1.0
+	 * @var array
+	 */
+	public static $layout_enum = array(
+		1 => 'nodisplay',
+		2 => 'fixed',
+		3 => 'fixed-height',
+		4 => 'responsive',
+		5 => 'container',
+		6 => 'fill',
+		7 => 'flex-item',
+		8 => 'fluid',
+		9 => 'intrinsic',
+	);
+
+	/**
+	 * List of boolean attributes.
+	 *
+	 * @since 0.7
+	 * @var array
+	 */
+	public static $boolean_attributes = array(
+		'allowfullscreen',
+		'async',
+		'autofocus',
+		'autoplay',
+		'checked',
+		'compact',
+		'controls',
+		'declare',
+		'default',
+		'defaultchecked',
+		'defaultmuted',
+		'defaultselected',
+		'defer',
+		'disabled',
+		'draggable',
+		'enabled',
+		'formnovalidate',
+		'hidden',
+		'indeterminate',
+		'inert',
+		'ismap',
+		'itemscope',
+		'loop',
+		'multiple',
+		'muted',
+		'nohref',
+		'noresize',
+		'noshade',
+		'novalidate',
+		'nowrap',
+		'open',
+		'pauseonexit',
+		'readonly',
+		'required',
+		'reversed',
+		'scoped',
+		'seamless',
+		'selected',
+		'sortable',
+		'spellcheck',
+		'translate',
+		'truespeed',
+		'typemustmatch',
+		'visible',
+	);
+
+	/**
+	 * Additional allowed tags.
+	 *
+	 * @var array
+	 */
+	public static $additional_allowed_tags = array(
+
+		// An experimental tag with no protoascii.
+		'amp-share-tracking' => array(
+			'attr_spec_list' => array(),
+			'tag_spec'       => array(),
+		),
+	);
+}
diff --git a/includes/sanitizers/class-amp-script-sanitizer.php b/includes/sanitizers/class-amp-script-sanitizer.php
new file mode 100644
index 00000000000..1e39e1cf394
--- /dev/null
+++ b/includes/sanitizers/class-amp-script-sanitizer.php
@@ -0,0 +1,49 @@
+<?php
+/**
+ * Class AMP_Script_Sanitizer
+ *
+ * @since 1.0
+ * @package AMP
+ */
+
+/**
+ * Class AMP_Script_Sanitizer
+ *
+ * @since 1.0
+ */
+class AMP_Script_Sanitizer extends AMP_Base_Sanitizer {
+
+	/**
+	 * Sanitize noscript elements.
+	 *
+	 * Eventually this should also handle script elements, if there is a known AMP equivalent.
+	 * If nothing is done with script elements, the whitelist sanitizer will deal with them ultimately.
+	 *
+	 * @todo Eventually this try to automatically convert script tags to AMP when they are recognized. See <https://github.com/Automattic/amp-wp/issues/1032>.
+	 * @todo When a script has an adjacent noscript, consider removing the script here to prevent validation error later. See <https://github.com/Automattic/amp-wp/issues/1213>.
+	 *
+	 * @since 1.0
+	 */
+	public function sanitize() {
+		$noscripts = $this->dom->getElementsByTagName( 'noscript' );
+
+		for ( $i = $noscripts->length - 1; $i >= 0; $i-- ) {
+			$noscript = $noscripts->item( $i );
+
+			// Skip AMP boilerplate.
+			if ( $noscript->firstChild instanceof DOMElement && $noscript->firstChild->hasAttribute( 'amp-boilerplate' ) ) {
+				continue;
+			}
+
+			$fragment = $this->dom->createDocumentFragment();
+			$fragment->appendChild( $this->dom->createComment( 'noscript' ) );
+			while ( $noscript->firstChild ) {
+				$fragment->appendChild( $noscript->firstChild );
+			}
+			$fragment->appendChild( $this->dom->createComment( '/noscript' ) );
+			$noscript->parentNode->replaceChild( $fragment, $noscript );
+
+			$this->did_convert_elements = true;
+		}
+	}
+}
diff --git a/includes/sanitizers/class-amp-style-sanitizer.php b/includes/sanitizers/class-amp-style-sanitizer.php
new file mode 100644
index 00000000000..6993a472a51
--- /dev/null
+++ b/includes/sanitizers/class-amp-style-sanitizer.php
@@ -0,0 +1,2225 @@
+<?php
+/**
+ * Class AMP_Style_Sanitizer
+ *
+ * @package AMP
+ */
+
+use \Sabberworm\CSS\RuleSet\DeclarationBlock;
+use \Sabberworm\CSS\CSSList\CSSList;
+use \Sabberworm\CSS\Property\Selector;
+use \Sabberworm\CSS\RuleSet\RuleSet;
+use \Sabberworm\CSS\Property\AtRule;
+use \Sabberworm\CSS\CSSList\KeyFrame;
+use \Sabberworm\CSS\RuleSet\AtRuleSet;
+use \Sabberworm\CSS\Property\Import;
+use \Sabberworm\CSS\CSSList\AtRuleBlockList;
+use \Sabberworm\CSS\Value\RuleValueList;
+use \Sabberworm\CSS\Value\URL;
+use \Sabberworm\CSS\CSSList\Document;
+
+/**
+ * Class AMP_Style_Sanitizer
+ *
+ * Collects inline styles and outputs them in the amp-custom stylesheet.
+ */
+class AMP_Style_Sanitizer extends AMP_Base_Sanitizer {
+
+	/**
+	 * Error code for tree shaking.
+	 *
+	 * @var string
+	 */
+	const TREE_SHAKING_ERROR_CODE = 'removed_unused_css_rules';
+
+	/**
+	 * Error code for illegal at-rule.
+	 *
+	 * @var string
+	 */
+	const ILLEGAL_AT_RULE_ERROR_CODE = 'illegal_css_at_rule';
+
+	/**
+	 * Inline style selector's specificity multiplier, i.e. used to generate the number of ':not(#_)' placeholders.
+	 *
+	 * @var int
+	 */
+	const INLINE_SPECIFICITY_MULTIPLIER = 5; // @todo The correctness of using "5" should be validated.
+
+	/**
+	 * Array of flags used to control sanitization.
+	 *
+	 * @var array {
+	 *      @type string   $remove_unused_rules        Enum 'never', 'sometimes' (default), 'always'. If total CSS is greater than max_bytes, whether to strip selectors (and then empty rules) when they are not found to be used in doc. A validation error will be emitted when stripping happens since it is not completely safe in the case of dynamic content.
+	 *      @type string[] $dynamic_element_selectors  Selectors for elements (or their ancestors) which contain dynamic content; selectors containing these will not be filtered.
+	 *      @type bool     $use_document_element       Whether the root of the document should be used rather than the body.
+	 *      @type bool     $require_https_src          Require HTTPS URLs.
+	 *      @type bool     $allow_dirty_styles         Allow dirty styles. This short-circuits the sanitize logic; it is used primarily in Customizer preview.
+	 *      @type callable $validation_error_callback  Function to call when a validation error is encountered.
+	 *      @type bool     $should_locate_sources      Whether to locate the sources when reporting validation errors.
+	 *      @type string   $parsed_cache_variant       Additional value by which to vary parsed cache.
+	 *      @type bool     $accept_tree_shaking        Whether to accept tree-shaking by default and bypass a validation error.
+	 * }
+	 */
+	protected $args;
+
+	/**
+	 * Default args.
+	 *
+	 * @var array
+	 */
+	protected $DEFAULT_ARGS = array(
+		'remove_unused_rules'       => 'sometimes',
+		'dynamic_element_selectors' => array(
+			'amp-list',
+			'amp-live-list',
+			'[submit-error]',
+			'[submit-success]',
+		),
+		'should_locate_sources'     => false,
+		'parsed_cache_variant'      => null,
+		'accept_tree_shaking'       => false,
+	);
+
+	/**
+	 * Stylesheets.
+	 *
+	 * Values are the CSS stylesheets. Keys are MD5 hashes of the stylesheets,
+	 *
+	 * @since 0.7
+	 * @var string[]
+	 */
+	private $stylesheets = array();
+
+	/**
+	 * List of stylesheet parts prior to selector/rule removal (tree shaking).
+	 *
+	 * Keys are MD5 hashes of stylesheets.
+	 *
+	 * @since 1.0
+	 * @var array[] {
+	 *     @type array              $stylesheet Array of stylesheet chunked, with declaration blocks being represented as arrays.
+	 *     @type DOMElement|DOMAttr $node       Origin for styles.
+	 *     @type array              $sources    Sources for the node.
+	 *     @type bool               $keyframes  Whether an amp-keyframes.
+	 * }
+	 */
+	private $pending_stylesheets = array();
+
+	/**
+	 * Spec for style[amp-custom] cdata.
+	 *
+	 * @since 1.0
+	 * @var array
+	 */
+	private $style_custom_cdata_spec;
+
+	/**
+	 * The style[amp-custom] element.
+	 *
+	 * @var DOMElement
+	 */
+	private $amp_custom_style_element;
+
+	/**
+	 * Spec for style[amp-keyframes] cdata.
+	 *
+	 * @since 1.0
+	 * @var array
+	 */
+	private $style_keyframes_cdata_spec;
+
+	/**
+	 * Regex for allowed font stylesheet URL.
+	 *
+	 * @var string
+	 */
+	private $allowed_font_src_regex;
+
+	/**
+	 * Base URL for styles.
+	 *
+	 * Full URL with trailing slash.
+	 *
+	 * @var string
+	 */
+	private $base_url;
+
+	/**
+	 * URL of the content directory.
+	 *
+	 * @var string
+	 */
+	private $content_url;
+
+	/**
+	 * Class names used in document.
+	 *
+	 * @since 1.0
+	 * @var array
+	 */
+	private $used_class_names = array();
+
+	/**
+	 * Tag names used in document.
+	 *
+	 * @since 1.0
+	 * @var array
+	 */
+	private $used_tag_names = array();
+
+	/**
+	 * XPath.
+	 *
+	 * @since 1.0
+	 * @var DOMXPath
+	 */
+	private $xpath;
+
+	/**
+	 * Amount of time that was spent parsing CSS.
+	 *
+	 * @since 1.0
+	 * @var float
+	 */
+	private $parse_css_duration = 0.0;
+
+	/**
+	 * THe HEAD element.
+	 *
+	 * @var DOMElement
+	 */
+	private $head;
+
+	/**
+	 * Current node being processed.
+	 *
+	 * @var DOMElement|DOMAttr
+	 */
+	private $current_node;
+
+	/**
+	 * Current sources for a given node.
+	 *
+	 * @var array
+	 */
+	private $current_sources;
+
+	/**
+	 * Log of the stylesheet URLs that have been imported to guard against infinite loops.
+	 *
+	 * @var array
+	 */
+	private $processed_imported_stylesheet_urls = array();
+
+	/**
+	 * List of font stylesheets that were @import'ed which should have been <link>'ed to instead.
+	 *
+	 * These font URLs will be cached with the parsed CSS and then converted into stylesheet links.
+	 *
+	 * @var array
+	 */
+	private $imported_font_urls = array();
+
+	/**
+	 * Mapping of HTML element selectors to AMP selector elements.
+	 *
+	 * @var array
+	 */
+	private $selector_mappings = array();
+
+	/**
+	 * Get error codes that can be raised during parsing of CSS.
+	 *
+	 * This is used to determine which validation errors should be taken into account
+	 * when determining which validation errors should vary the parse cache.
+	 *
+	 * @return array
+	 */
+	public static function get_css_parser_validation_error_codes() {
+		return array(
+			'css_parse_error',
+			'excessive_css',
+			self::ILLEGAL_AT_RULE_ERROR_CODE,
+			'illegal_css_important',
+			'illegal_css_property',
+			self::TREE_SHAKING_ERROR_CODE,
+			'unrecognized_css',
+			'disallowed_file_extension',
+			'file_path_not_found',
+		);
+	}
+
+	/**
+	 * AMP_Base_Sanitizer constructor.
+	 *
+	 * @since 0.7
+	 *
+	 * @param DOMDocument $dom  Represents the HTML document to sanitize.
+	 * @param array       $args Args.
+	 */
+	public function __construct( DOMDocument $dom, array $args = array() ) {
+		parent::__construct( $dom, $args );
+
+		foreach ( AMP_Allowed_Tags_Generated::get_allowed_tag( 'style' ) as $spec_rule ) {
+			if ( ! isset( $spec_rule[ AMP_Rule_Spec::TAG_SPEC ]['spec_name'] ) ) {
+				continue;
+			}
+			if ( 'style[amp-keyframes]' === $spec_rule[ AMP_Rule_Spec::TAG_SPEC ]['spec_name'] ) {
+				$this->style_keyframes_cdata_spec = $spec_rule[ AMP_Rule_Spec::CDATA ];
+			} elseif ( 'style amp-custom' === $spec_rule[ AMP_Rule_Spec::TAG_SPEC ]['spec_name'] ) {
+				$this->style_custom_cdata_spec = $spec_rule[ AMP_Rule_Spec::CDATA ];
+			}
+		}
+
+		$spec_name = 'link rel=stylesheet for fonts'; // phpcs:ignore WordPress.WP.EnqueuedResources.NonEnqueuedStylesheet
+		foreach ( AMP_Allowed_Tags_Generated::get_allowed_tag( 'link' ) as $spec_rule ) {
+			if ( isset( $spec_rule[ AMP_Rule_Spec::TAG_SPEC ]['spec_name'] ) && $spec_name === $spec_rule[ AMP_Rule_Spec::TAG_SPEC ]['spec_name'] ) {
+				$this->allowed_font_src_regex = '@^(' . $spec_rule[ AMP_Rule_Spec::ATTR_SPEC_LIST ]['href']['value_regex'] . ')$@';
+				break;
+			}
+		}
+
+		$guessurl = site_url();
+		if ( ! $guessurl ) {
+			$guessurl = wp_guess_url();
+		}
+		$this->base_url    = $guessurl;
+		$this->content_url = WP_CONTENT_URL;
+		$this->xpath       = new DOMXPath( $dom );
+	}
+
+	/**
+	 * Get list of CSS styles in HTML content of DOMDocument ($this->dom).
+	 *
+	 * @since 0.4
+	 * @deprecated As of 1.0, use get_stylesheets().
+	 *
+	 * @return array[] Mapping CSS selectors to array of properties, or mapping of keys starting with 'stylesheet:' with value being the stylesheet.
+	 */
+	public function get_styles() {
+		return array();
+	}
+
+	/**
+	 * Get stylesheets.
+	 *
+	 * @since 0.7
+	 * @returns array Values are the CSS stylesheets. Keys are MD5 hashes of the stylesheets.
+	 */
+	public function get_stylesheets() {
+		return $this->stylesheets;
+	}
+
+	/**
+	 * Get list of all the class names used in the document, including those used in [class] attributes.
+	 *
+	 * @since 1.0
+	 * @return array Used class names.
+	 */
+	private function get_used_class_names() {
+		if ( empty( $this->used_class_names ) ) {
+			$classes = ' ';
+			foreach ( $this->xpath->query( '//*/@class' ) as $class_attribute ) {
+				$classes .= ' ' . $class_attribute->nodeValue;
+			}
+
+			// Find all [class] attributes and capture the contents of any single- or double-quoted strings.
+			foreach ( $this->xpath->query( '//*/@' . AMP_DOM_Utils::get_amp_bind_placeholder_prefix() . 'class' ) as $bound_class_attribute ) {
+				if ( preg_match_all( '/([\'"])([^\1]*?)\1/', $bound_class_attribute->nodeValue, $matches ) ) {
+					$classes .= ' ' . implode( ' ', $matches[2] );
+				}
+			}
+
+			$this->used_class_names = array_unique( array_filter( preg_split( '/\s+/', trim( $classes ) ) ) );
+		}
+		return $this->used_class_names;
+	}
+
+
+	/**
+	 * Get list of all the tag names used in the document.
+	 *
+	 * @since 1.0
+	 * @return array Used tag names.
+	 */
+	private function get_used_tag_names() {
+		if ( empty( $this->used_tag_names ) ) {
+			$used_tag_names = array();
+			foreach ( $this->dom->getElementsByTagName( '*' ) as $el ) {
+				$used_tag_names[ $el->tagName ] = true;
+			}
+			$this->used_tag_names = array_keys( $used_tag_names );
+		}
+		return $this->used_tag_names;
+	}
+
+	/**
+	 * Run logic before any sanitizers are run.
+	 *
+	 * After the sanitizers are instantiated but before calling sanitize on each of them, this
+	 * method is called with list of all the instantiated sanitizers.
+	 *
+	 * @param AMP_Base_Sanitizer[] $sanitizers Sanitizers.
+	 */
+	public function init( $sanitizers ) {
+		parent::init( $sanitizers );
+
+		foreach ( $sanitizers as $sanitizer ) {
+			foreach ( $sanitizer->get_selector_conversion_mapping() as $html_selectors => $amp_selectors ) {
+				if ( ! isset( $this->selector_mappings[ $html_selectors ] ) ) {
+					$this->selector_mappings[ $html_selectors ] = $amp_selectors;
+				} else {
+					$this->selector_mappings[ $html_selectors ] = array_unique(
+						array_merge( $this->selector_mappings[ $html_selectors ], $amp_selectors )
+					);
+				}
+
+				// Prevent selectors like `amp-img img` getting deleted since `img` does not occur in the DOM.
+				$this->args['dynamic_element_selectors'] = array_merge(
+					$this->args['dynamic_element_selectors'],
+					$this->selector_mappings[ $html_selectors ]
+				);
+			}
+		}
+	}
+
+	/**
+	 * Sanitize CSS styles within the HTML contained in this instance's DOMDocument.
+	 *
+	 * @since 0.4
+	 */
+	public function sanitize() {
+		$elements = array();
+
+		// Do nothing if inline styles are allowed.
+		if ( ! empty( $this->args['allow_dirty_styles'] ) ) {
+			return;
+		}
+
+		$this->head = $this->dom->getElementsByTagName( 'head' )->item( 0 );
+		if ( ! $this->head ) {
+			$this->head = $this->dom->createElement( 'head' );
+			$this->dom->documentElement->insertBefore( $this->head, $this->dom->documentElement->firstChild );
+		}
+
+		$this->parse_css_duration = 0.0;
+
+		/*
+		 * Note that xpath is used to query the DOM so that the link and style elements will be
+		 * in document order. DOMNode::compareDocumentPosition() is not yet implemented.
+		 */
+		$xpath = $this->xpath;
+
+		$lower_case = 'translate( %s, "ABCDEFGHIJKLMNOPQRSTUVWXYZ", "abcdefghijklmnopqrstuvwxyz" )'; // In XPath 2.0 this is lower-case().
+		$predicates = array(
+			sprintf( '( self::style and not( @amp-boilerplate ) and ( not( @type ) or %s = "text/css" ) )', sprintf( $lower_case, '@type' ) ),
+			sprintf( '( self::link and @href and %s = "stylesheet" )', sprintf( $lower_case, '@rel' ) ),
+		);
+
+		foreach ( $xpath->query( '//*[ ' . implode( ' or ', $predicates ) . ' ]' ) as $element ) {
+			$elements[] = $element;
+		}
+
+		// If 'width' attribute is present for 'col' tag, convert to proper CSS rule.
+		foreach ( $this->dom->getElementsByTagName( 'col' ) as $col ) {
+			/**
+			 * Col element.
+			 *
+			 * @var DOMElement $col
+			 */
+			$width_attr = $col->getAttribute( 'width' );
+			if ( ! empty( $width_attr ) && ( false === strpos( $width_attr, '*' ) ) ) {
+				$width_style = 'width: ' . $width_attr;
+				if ( is_numeric( $width_attr ) ) {
+					$width_style .= 'px';
+				}
+				if ( $col->hasAttribute( 'style' ) ) {
+					$col->setAttribute( 'style', $width_style . ';' . $col->getAttribute( 'style' ) );
+				} else {
+					$col->setAttribute( 'style', $width_style );
+				}
+				$col->removeAttribute( 'width' );
+			}
+		}
+
+		/**
+		 * Element.
+		 *
+		 * @var DOMElement $element
+		 */
+		foreach ( $elements as $element ) {
+			$node_name = strtolower( $element->nodeName );
+			if ( 'style' === $node_name ) {
+				$this->process_style_element( $element );
+			} elseif ( 'link' === $node_name ) {
+				$this->process_link_element( $element );
+			}
+		}
+
+		$elements = array();
+		foreach ( $xpath->query( '//*[ @style ]' ) as $element ) {
+			$elements[] = $element;
+		}
+		foreach ( $elements as $element ) {
+			$this->collect_inline_styles( $element );
+		}
+
+		$this->finalize_styles();
+
+		$this->did_convert_elements = true;
+
+		if ( $this->parse_css_duration > 0.0 ) {
+			AMP_HTTP::send_server_timing( 'amp_parse_css', $this->parse_css_duration, 'AMP Parse CSS' );
+		}
+	}
+
+	/**
+	 * Generate a URL's fully-qualified file path.
+	 *
+	 * @since 0.7
+	 * @see WP_Styles::_css_href()
+	 *
+	 * @param string   $url The file URL.
+	 * @param string[] $allowed_extensions Allowed file extensions for local files.
+	 * @return string|WP_Error Style's absolute validated filesystem path, or WP_Error when error.
+	 */
+	public function get_validated_url_file_path( $url, $allowed_extensions = array() ) {
+		$needs_base_url = (
+			! is_bool( $url )
+			&&
+			! preg_match( '|^(https?:)?//|', $url )
+			&&
+			! ( $this->content_url && 0 === strpos( $url, $this->content_url ) )
+		);
+		if ( $needs_base_url ) {
+			$url = $this->base_url . $url;
+		}
+
+		$remove_url_scheme = function( $schemed_url ) {
+			return preg_replace( '#^\w+:(?=//)#', '', $schemed_url );
+		};
+
+		// Strip URL scheme, query, and fragment.
+		$url = $remove_url_scheme( preg_replace( ':[\?#].*$:', '', $url ) );
+
+		$includes_url = $remove_url_scheme( includes_url( '/' ) );
+		$content_url  = $remove_url_scheme( content_url( '/' ) );
+		$admin_url    = $remove_url_scheme( get_admin_url( null, '/' ) );
+
+		$allowed_hosts = array(
+			wp_parse_url( $includes_url, PHP_URL_HOST ),
+			wp_parse_url( $content_url, PHP_URL_HOST ),
+			wp_parse_url( $admin_url, PHP_URL_HOST ),
+		);
+
+		$url_host = wp_parse_url( $url, PHP_URL_HOST );
+
+		// Validate file extensions.
+		if ( ! empty( $allowed_extensions ) ) {
+			$pattern = sprintf( '/\.(%s)$/i', implode( '|', $allowed_extensions ) );
+			if ( ! preg_match( $pattern, $url ) ) {
+				/* translators: %s: the file URL. */
+				return new WP_Error( 'disallowed_file_extension', sprintf( __( 'File does not have an allowed file extension for filesystem access (%s).', 'amp' ), $url ) );
+			}
+		}
+
+		if ( ! in_array( $url_host, $allowed_hosts, true ) ) {
+			/* translators: %s: the file URL */
+			return new WP_Error( 'external_file_url', sprintf( __( 'URL is located on an external domain: %s.', 'amp' ), $url_host ) );
+		}
+
+		$base_path = null;
+		$file_path = null;
+		if ( 0 === strpos( $url, $content_url ) ) {
+			$base_path = WP_CONTENT_DIR;
+			$file_path = substr( $url, strlen( $content_url ) - 1 );
+		} elseif ( 0 === strpos( $url, $includes_url ) ) {
+			$base_path = ABSPATH . WPINC;
+			$file_path = substr( $url, strlen( $includes_url ) - 1 );
+		} elseif ( 0 === strpos( $url, $admin_url ) ) {
+			$base_path = ABSPATH . 'wp-admin';
+			$file_path = substr( $url, strlen( $admin_url ) - 1 );
+		}
+
+		if ( ! $file_path || false !== strpos( $file_path, '../' ) || false !== strpos( $file_path, '..\\' ) ) {
+			/* translators: %s: the file URL. */
+			return new WP_Error( 'file_path_not_allowed', sprintf( __( 'Disallowed URL filesystem path for %s.', 'amp' ), $url ) );
+		}
+		if ( ! file_exists( $base_path . $file_path ) ) {
+			/* translators: %s: the file URL. */
+			return new WP_Error( 'file_path_not_found', sprintf( __( 'Unable to locate filesystem path for %s.', 'amp' ), $url ) );
+		}
+
+		return $base_path . $file_path;
+	}
+
+	/**
+	 * Set the current node (and its sources when required).
+	 *
+	 * @since 1.0
+	 * @param DOMElement|DOMAttr|null $node Current node, or null to reset.
+	 */
+	private function set_current_node( $node ) {
+		if ( $this->current_node === $node ) {
+			return;
+		}
+
+		$this->current_node = $node;
+		if ( empty( $node ) ) {
+			$this->current_sources = null;
+		} elseif ( ! empty( $this->args['should_locate_sources'] ) ) {
+			$this->current_sources = AMP_Validation_Manager::locate_sources( $node );
+		}
+	}
+
+	/**
+	 * Process style element.
+	 *
+	 * @param DOMElement $element Style element.
+	 */
+	private function process_style_element( DOMElement $element ) {
+		$this->set_current_node( $element ); // And sources when needing to be located.
+
+		// @todo Any @keyframes rules could be removed from amp-custom and instead added to amp-keyframes.
+		$is_keyframes = $element->hasAttribute( 'amp-keyframes' );
+		$stylesheet   = trim( $element->textContent );
+		$cdata_spec   = $is_keyframes ? $this->style_keyframes_cdata_spec : $this->style_custom_cdata_spec;
+
+		// Honor the style's media attribute.
+		$media = $element->getAttribute( 'media' );
+		if ( $media && 'all' !== $media ) {
+			$stylesheet = sprintf( '@media %s { %s }', $media, $stylesheet );
+		}
+
+		$processed = $this->process_stylesheet( $stylesheet, array(
+			'allowed_at_rules'   => $cdata_spec['css_spec']['allowed_at_rules'],
+			'property_whitelist' => $cdata_spec['css_spec']['declaration'],
+			'validate_keyframes' => $cdata_spec['css_spec']['validate_keyframes'],
+		) );
+
+		$this->pending_stylesheets[] = array_merge(
+			array(
+				'keyframes' => $is_keyframes,
+				'node'      => $element,
+				'sources'   => $this->current_sources,
+			),
+			wp_array_slice_assoc( $processed, array( 'stylesheet', 'imported_font_urls' ) )
+		);
+
+		if ( $element->hasAttribute( 'amp-custom' ) ) {
+			if ( ! $this->amp_custom_style_element ) {
+				$this->amp_custom_style_element = $element;
+			} else {
+				$element->parentNode->removeChild( $element ); // There can only be one. #highlander.
+			}
+		} else {
+
+			// Remove from DOM since we'll be adding it to amp-custom.
+			$element->parentNode->removeChild( $element );
+		}
+
+		$this->set_current_node( null );
+	}
+
+	/**
+	 * Process link element.
+	 *
+	 * @param DOMElement $element Link element.
+	 */
+	private function process_link_element( DOMElement $element ) {
+		$href = $element->getAttribute( 'href' );
+
+		// Allow font URLs, including protocol-less URLs and recognized URLs that use HTTP instead of HTTPS.
+		$normalized_url = preg_replace( '#^(http:)?(?=//)#', 'https:', $href );
+		if ( $this->allowed_font_src_regex && preg_match( $this->allowed_font_src_regex, $normalized_url ) ) {
+			if ( $href !== $normalized_url ) {
+				$element->setAttribute( 'href', $normalized_url );
+			}
+
+			/*
+			 * Make sure rel=preconnect link is present for Google Fonts stylesheet.
+			 * Note that core themes normally do this already, per <https://core.trac.wordpress.org/ticket/37171>.
+			 * But not always, per <https://core.trac.wordpress.org/ticket/44668>.
+			 * This also ensures that other themes will get the preconnect link when
+			 * they don't implement the resource hint.
+			 */
+			$needs_preconnect_link = (
+				'https://fonts.googleapis.com/' === substr( $normalized_url, 0, 29 )
+				&&
+				0 === $this->xpath->query( '//link[ @rel = "preconnect" and @crossorigin and starts-with( @href, "https://fonts.gstatic.com" ) ]', $this->head )->length
+			);
+			if ( $needs_preconnect_link ) {
+				$link = AMP_DOM_Utils::create_node( $this->dom, 'link', array(
+					'rel'         => 'preconnect',
+					'href'        => 'https://fonts.gstatic.com/',
+					'crossorigin' => '',
+				) );
+				$this->head->insertBefore( $link ); // Note that \AMP_Theme_Support::ensure_required_markup() will put this in the optimal order.
+			}
+			return;
+		}
+
+		$css_file_path = $this->get_validated_url_file_path( $href, array( 'css', 'less', 'scss', 'sass' ) );
+
+		if ( is_wp_error( $css_file_path ) && ( 'disallowed_file_extension' === $css_file_path->get_error_code() || 'external_file_url' === $css_file_path->get_error_code() ) ) {
+			$contents = $this->fetch_external_stylesheet( $normalized_url );
+			if ( is_wp_error( $contents ) ) {
+				$this->remove_invalid_child( $element, array(
+					'code'    => $css_file_path->get_error_code(),
+					'message' => $css_file_path->get_error_message(),
+					'type'    => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
+				) );
+				return;
+			} else {
+				$stylesheet = $contents;
+			}
+		} elseif ( is_wp_error( $css_file_path ) ) {
+			$this->remove_invalid_child( $element, array(
+				'code'    => $css_file_path->get_error_code(),
+				'message' => $css_file_path->get_error_message(),
+				'type'    => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
+			) );
+			return;
+		} else {
+			$stylesheet = file_get_contents( $css_file_path ); // phpcs:ignore -- It's a local filesystem path not a remote request.
+		}
+
+		if ( false === $stylesheet ) {
+			$this->remove_invalid_child( $element, array(
+				'code' => 'stylesheet_file_missing',
+				'type' => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
+			) );
+			return;
+		}
+
+		// Honor the link's media attribute.
+		$media = $element->getAttribute( 'media' );
+		if ( $media && 'all' !== $media ) {
+			$stylesheet = sprintf( '@media %s { %s }', $media, $stylesheet );
+		}
+
+		$this->set_current_node( $element ); // And sources when needing to be located.
+
+		$processed = $this->process_stylesheet( $stylesheet, array(
+			'allowed_at_rules'   => $this->style_custom_cdata_spec['css_spec']['allowed_at_rules'],
+			'property_whitelist' => $this->style_custom_cdata_spec['css_spec']['declaration'],
+			'stylesheet_url'     => $href,
+			'stylesheet_path'    => $css_file_path,
+		) );
+
+		$this->pending_stylesheets[] = array_merge(
+			array(
+				'keyframes' => false,
+				'node'      => $element,
+				'sources'   => $this->current_sources, // Needed because node is removed below.
+			),
+			wp_array_slice_assoc( $processed, array( 'stylesheet', 'imported_font_urls' ) )
+		);
+
+		// Remove now that styles have been processed.
+		$element->parentNode->removeChild( $element );
+
+		$this->set_current_node( null );
+	}
+
+	/**
+	 * Fetch external stylesheet.
+	 *
+	 * @param string $url External stylesheet URL.
+	 * @return string|WP_Error Stylesheet contents or WP_Error.
+	 */
+	private function fetch_external_stylesheet( $url ) {
+		$cache_key = md5( $url );
+		$contents  = get_transient( $cache_key );
+		if ( false === $contents ) {
+			$r = wp_remote_get( $url );
+			if ( 200 !== wp_remote_retrieve_response_code( $r ) ) {
+				$contents = new WP_Error(
+					wp_remote_retrieve_response_code( $r ),
+					wp_remote_retrieve_response_message( $r )
+				);
+			} else {
+				$contents = wp_remote_retrieve_body( $r );
+			}
+			set_transient( $cache_key, $contents, MONTH_IN_SECONDS );
+		}
+		return $contents;
+	}
+
+	/**
+	 * Process stylesheet.
+	 *
+	 * Sanitized invalid CSS properties and rules, removes rules which do not
+	 * apply to the current document, and compresses the CSS to remove whitespace and comments.
+	 *
+	 * @since 1.0
+	 *
+	 * @param string $stylesheet Stylesheet.
+	 * @param array  $options {
+	 *     Options.
+	 *
+	 *     @type string[] $property_whitelist          Exclusively-allowed properties.
+	 *     @type string[] $property_blacklist          Disallowed properties.
+	 *     @type string   $stylesheet_url              Original URL for stylesheet when originating via link or @import.
+	 *     @type string   $stylesheet_path             Original filesystem path for stylesheet when originating via link or @import.
+	 *     @type array    $allowed_at_rules            Allowed @-rules.
+	 *     @type bool     $validate_keyframes          Whether keyframes should be validated.
+	 * }
+	 * @return array {
+	 *    Processed stylesheet.
+	 *
+	 *    @type array $stylesheet         Stylesheet parts, where arrays are tuples for declaration blocks.
+	 *    @type array $validation_results Validation results, array containing arrays with error and sanitized keys.
+	 *    @type array $imported_font_urls Imported font stylesheet URLs.
+	 * }
+	 */
+	private function process_stylesheet( $stylesheet, $options = array() ) {
+		$parsed      = null;
+		$cache_key   = null;
+		$cache_group = 'amp-parsed-stylesheet-v13'; // This should be bumped whenever the PHP-CSS-Parser is updated.
+
+		$cache_impacting_options = array_merge(
+			wp_array_slice_assoc(
+				$options,
+				array( 'property_whitelist', 'property_blacklist', 'stylesheet_url', 'allowed_at_rules' )
+			),
+			wp_array_slice_assoc(
+				$this->args,
+				array( 'should_locate_sources', 'parsed_cache_variant' )
+			),
+			array(
+				'language' => get_bloginfo( 'language' ), // Used to tree-shake html[lang] selectors.
+			)
+		);
+
+		$cache_key = md5( $stylesheet . wp_json_encode( $cache_impacting_options ) );
+
+		if ( wp_using_ext_object_cache() ) {
+			$parsed = wp_cache_get( $cache_key, $cache_group );
+		} else {
+			$parsed = get_transient( $cache_key . $cache_group );
+		}
+
+		/*
+		 * Make sure that the parsed stylesheet was cached with current sanitizations.
+		 * The should_sanitize_validation_error method prevents duplicates from being reported.
+		 */
+		if ( ! empty( $parsed['validation_results'] ) ) {
+			foreach ( $parsed['validation_results'] as $validation_result ) {
+				$sanitized = $this->should_sanitize_validation_error( $validation_result['error'] );
+				if ( $sanitized !== $validation_result['sanitized'] ) {
+					$parsed = null; // Change to sanitization of validation error detected, so cache cannot be used.
+					break;
+				}
+			}
+		}
+
+		if ( ! $parsed || ! isset( $parsed['stylesheet'] ) || ! is_array( $parsed['stylesheet'] ) ) {
+			$parsed = $this->prepare_stylesheet( $stylesheet, $options );
+
+			/*
+			 * When an object cache is not available, we cache with an expiration to prevent the options table from
+			 * getting filled infinitely. On the other hand, if an external object cache is available then we don't
+			 * set an expiration because it should implement LRU cache expulsion policy.
+			 */
+			if ( wp_using_ext_object_cache() ) {
+				wp_cache_set( $cache_key, $parsed, $cache_group );
+			} else {
+				// The expiration is to ensure transient doesn't stick around forever since no LRU flushing like with external object cache.
+				set_transient( $cache_key . $cache_group, $parsed, MONTH_IN_SECONDS );
+			}
+		}
+
+		return $parsed;
+	}
+
+	/**
+	 * Parse imported stylesheet.
+	 *
+	 * @param Import  $item     Import object.
+	 * @param CSSList $css_list CSS List.
+	 * @param array   $options {
+	 *     Options.
+	 *
+	 *     @type string $stylesheet_url Original URL for stylesheet when originating via link or @import.
+	 * }
+	 * @return array Validation results.
+	 */
+	private function parse_import_stylesheet( Import $item, CSSList $css_list, $options ) {
+		$results      = array();
+		$at_rule_args = $item->atRuleArgs();
+		$location     = array_shift( $at_rule_args );
+		$media_query  = array_shift( $at_rule_args );
+
+		if ( isset( $options['stylesheet_url'] ) ) {
+			$this->real_path_urls( array( $location ), $options['stylesheet_url'] );
+		}
+
+		$import_stylesheet_url = $location->getURL()->getString();
+
+		// Prevent importing something that has already been imported, and avoid infinite recursion.
+		if ( isset( $this->processed_imported_stylesheet_urls[ $import_stylesheet_url ] ) ) {
+			$css_list->remove( $item );
+			return array();
+		}
+		$this->processed_imported_stylesheet_urls[ $import_stylesheet_url ] = true;
+
+		// Prevent importing font stylesheets from allowed font CDNs. These will get added to the document as links instead.
+		$https_import_stylesheet_url = preg_replace( '#^(http:)?(?=//)#', 'https:', $import_stylesheet_url );
+		if ( $this->allowed_font_src_regex && preg_match( $this->allowed_font_src_regex, $https_import_stylesheet_url ) ) {
+			$this->imported_font_urls[] = $https_import_stylesheet_url;
+			$css_list->remove( $item );
+			_doing_it_wrong(
+				'wp_enqueue_style',
+				esc_html( sprintf(
+					/* translators: %s is URL to font CDN */
+					__( 'It is not a best practice to use @import to load font CDN stylesheets. Please use wp_enqueue_style() to enqueue %s as its own separate script.', 'amp' ),
+					$import_stylesheet_url
+				) ),
+				'1.0'
+			);
+			return array();
+		}
+
+		$css_file_path = $this->get_validated_url_file_path( $import_stylesheet_url, array( 'css', 'less', 'scss', 'sass' ) );
+
+		if ( is_wp_error( $css_file_path ) && ( 'disallowed_file_extension' === $css_file_path->get_error_code() || 'external_file_url' === $css_file_path->get_error_code() ) ) {
+			$contents = $this->fetch_external_stylesheet( $import_stylesheet_url );
+			if ( is_wp_error( $contents ) ) {
+				$error     = array(
+					'code'    => $contents->get_error_code(),
+					'message' => $contents->get_error_message(),
+					'type'    => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
+				);
+				$sanitized = $this->should_sanitize_validation_error( $error );
+				if ( $sanitized ) {
+					$css_list->remove( $item );
+				}
+				$results[] = compact( 'error', 'sanitized' );
+				return $results;
+			} else {
+				$stylesheet = $contents;
+			}
+		} elseif ( is_wp_error( $css_file_path ) ) {
+			$error     = array(
+				'code'    => $css_file_path->get_error_code(),
+				'message' => $css_file_path->get_error_message(),
+				'type'    => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
+			);
+			$sanitized = $this->should_sanitize_validation_error( $error );
+			if ( $sanitized ) {
+				$css_list->remove( $item );
+			}
+			$results[] = compact( 'error', 'sanitized' );
+			return $results;
+		} else {
+			$stylesheet = file_get_contents( $css_file_path ); // phpcs:ignore -- It's a local filesystem path not a remote request.
+		}
+
+		if ( $media_query ) {
+			$stylesheet = sprintf( '@media %s { %s }', $media_query, $stylesheet );
+		}
+
+		$options['stylesheet_url'] = $import_stylesheet_url;
+
+		$parsed_stylesheet = $this->parse_stylesheet( $stylesheet, $options );
+
+		$results = array_merge(
+			$results,
+			$parsed_stylesheet['validation_results']
+		);
+
+		/**
+		 * CSS Doc.
+		 *
+		 * @var Document $css_document
+		 */
+		$css_document = $parsed_stylesheet['css_document'];
+
+		if ( ! empty( $parsed_stylesheet['css_document'] ) ) {
+			$css_list->replace( $item, $css_document->getContents() );
+		} else {
+			$css_list->remove( $item );
+		}
+
+		return $results;
+	}
+
+	/**
+	 * Parse stylesheet.
+	 *
+	 * @since 1.0
+	 *
+	 * @param string $stylesheet_string Stylesheet.
+	 * @param array  $options           Options. See definition in \AMP_Style_Sanitizer::process_stylesheet().
+	 * @return array {
+	 *    Parsed stylesheet.
+	 *
+	 *    @type Document $css_document       CSS Document.
+	 *    @type array    $validation_results Validation results, array containing arrays with error and sanitized keys.
+	 * }
+	 */
+	private function parse_stylesheet( $stylesheet_string, $options ) {
+		$validation_results = array();
+		$css_document       = null;
+
+		$this->imported_font_urls = array();
+		try {
+			// Remove spaces from data URLs, which cause errors and PHP-CSS-Parser can't handle them.
+			$stylesheet_string = $this->remove_spaces_from_data_urls( $stylesheet_string );
+
+			$parser_settings = Sabberworm\CSS\Settings::create();
+			$css_parser      = new Sabberworm\CSS\Parser( $stylesheet_string, $parser_settings );
+			$css_document    = $css_parser->parse(); // @todo If 'utf-8' is not $css_parser->getCharset() then issue warning?
+
+			if ( ! empty( $options['stylesheet_url'] ) ) {
+				$this->real_path_urls(
+					array_filter(
+						$css_document->getAllValues(),
+						function ( $value ) {
+							return $value instanceof URL;
+						}
+					),
+					$options['stylesheet_url']
+				);
+			}
+
+			$validation_results = array_merge(
+				$validation_results,
+				$this->process_css_list( $css_document, $options )
+			);
+		} catch ( Exception $exception ) {
+			$error = array(
+				'code'    => 'css_parse_error',
+				'message' => $exception->getMessage(),
+				'type'    => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
+			);
+
+			/*
+			 * This is not a recoverable error, so sanitized here is just used to give user control
+			 * over whether to proceed with serving this exception-raising stylesheet in AMP.
+			 */
+			$sanitized = $this->should_sanitize_validation_error( $error );
+
+			$validation_results[] = compact( 'error', 'sanitized' );
+		}
+		return array_merge(
+			compact( 'validation_results', 'css_document' ),
+			array(
+				'imported_font_urls' => $this->imported_font_urls,
+			)
+		);
+	}
+
+	/**
+	 * Prepare stylesheet.
+	 *
+	 * @since 1.0
+	 *
+	 * @param string $stylesheet_string Stylesheet.
+	 * @param array  $options           Options. See definition in \AMP_Style_Sanitizer::process_stylesheet().
+	 * @return array {
+	 *    Prepared stylesheet.
+	 *
+	 *    @type array $stylesheet         Stylesheet parts, where arrays are tuples for declaration blocks.
+	 *    @type array $validation_results Validation results, array containing arrays with error and sanitized keys.
+	 *    @type array $imported_font_urls Imported font stylesheet URLs.
+	 * }
+	 */
+	private function prepare_stylesheet( $stylesheet_string, $options = array() ) {
+		$start_time = microtime( true );
+
+		$options = array_merge(
+			array(
+				'allowed_at_rules'   => array(),
+				'property_blacklist' => array(
+					// See <https://www.ampproject.org/docs/design/responsive/style_pages#disallowed-styles>.
+					'behavior',
+					'-moz-binding',
+				),
+				'property_whitelist' => array(),
+				'validate_keyframes' => false,
+				'stylesheet_url'     => null,
+				'stylesheet_path'    => null,
+			),
+			$options
+		);
+
+		// Strip the dreaded UTF-8 byte order mark (BOM, \uFEFF). This should ideally get handled by PHP-CSS-Parser <https://github.com/sabberworm/PHP-CSS-Parser/issues/150>.
+		$stylesheet_string = preg_replace( '/^\xEF\xBB\xBF/', '', $stylesheet_string );
+
+		$stylesheet         = array();
+		$parsed_stylesheet  = $this->parse_stylesheet( $stylesheet_string, $options );
+		$validation_results = $parsed_stylesheet['validation_results'];
+		if ( ! empty( $parsed_stylesheet['css_document'] ) ) {
+			$css_document = $parsed_stylesheet['css_document'];
+
+			$output_format = Sabberworm\CSS\OutputFormat::createCompact();
+			$output_format->setSemicolonAfterLastRule( false );
+
+			$before_declaration_block          = '/*AMP_WP_BEFORE_DECLARATION_BLOCK*/';
+			$between_selectors                 = '/*AMP_WP_BETWEEN_SELECTORS*/';
+			$after_declaration_block_selectors = '/*AMP_WP_BEFORE_DECLARATION_SELECTORS*/';
+			$after_declaration_block           = '/*AMP_WP_AFTER_DECLARATION*/';
+			$before_at_rule                    = '/*AMP_WP_BEFORE_AT_RULE*/';
+			$after_at_rule                     = '/*AMP_WP_AFTER_AT_RULE*/';
+
+			$output_format->set( 'BeforeDeclarationBlock', $before_declaration_block );
+			$output_format->set( 'SpaceBeforeSelectorSeparator', $between_selectors );
+			$output_format->set( 'AfterDeclarationBlockSelectors', $after_declaration_block_selectors );
+			$output_format->set( 'AfterDeclarationBlock', $after_declaration_block );
+			$output_format->set( 'BeforeAtRuleBlock', $before_at_rule );
+			$output_format->set( 'AfterAtRuleBlock', $after_at_rule );
+
+			$stylesheet_string = $css_document->render( $output_format );
+
+			$pattern  = '#';
+			$pattern .= preg_quote( $before_at_rule, '#' );
+			$pattern .= '|';
+			$pattern .= preg_quote( $after_at_rule, '#' );
+			$pattern .= '|';
+			$pattern .= '(' . preg_quote( $before_declaration_block, '#' ) . ')';
+			$pattern .= '(.+?)';
+			$pattern .= preg_quote( $after_declaration_block_selectors, '#' );
+			$pattern .= '(.+?)';
+			$pattern .= preg_quote( $after_declaration_block, '#' );
+			$pattern .= '#s';
+
+			$dynamic_selector_pattern = null;
+			if ( ! empty( $this->args['dynamic_element_selectors'] ) ) {
+				$dynamic_selector_pattern = implode( '|', array_map(
+					function( $selector ) {
+						return preg_quote( $selector, '#' );
+					},
+					$this->args['dynamic_element_selectors']
+				) );
+			}
+
+			$split_stylesheet = preg_split( $pattern, $stylesheet_string, -1, PREG_SPLIT_DELIM_CAPTURE );
+			$length           = count( $split_stylesheet );
+			for ( $i = 0; $i < $length; $i++ ) {
+				if ( $before_declaration_block === $split_stylesheet[ $i ] ) {
+
+					// Skip keyframe-selector, which is can be: from | to | <percentage>.
+					if ( preg_match( '/^((from|to)\b|-?\d+(\.\d+)?%)/i', $split_stylesheet[ $i + 1 ] ) ) {
+						$stylesheet[] = str_replace( $between_selectors, '', $split_stylesheet[ ++$i ] ) . $split_stylesheet[ ++$i ];
+						continue;
+					}
+
+					$selectors   = explode( $between_selectors . ',', $split_stylesheet[ ++$i ] );
+					$declaration = $split_stylesheet[ ++$i ];
+
+					$selectors_parsed = array();
+					foreach ( $selectors as $selector ) {
+						$selectors_parsed[ $selector ] = array();
+
+						// Remove :not() and pseudo selectors to eliminate false negatives, such as with `body:not(.title-tagline-hidden) .site-branding-text`.
+						$reduced_selector = preg_replace( '/:[a-zA-Z0-9_-]+(\(.+?\))?/', '', $selector );
+
+						// Remove attribute selectors to eliminate false negative, such as with `.social-navigation a[href*="example.com"]:before`.
+						$reduced_selector = preg_replace( '/\[\w.*?\]/', '', $reduced_selector );
+
+						// Ignore any selector terms that occur under a dynamic selector.
+						if ( $dynamic_selector_pattern ) {
+							$reduced_selector = preg_replace( '#((?:' . $dynamic_selector_pattern . ')(?:\.[a-z0-9_-]+)*)[^a-z0-9_-].*#si', '$1', $reduced_selector . ' ' );
+						}
+
+						$reduced_selector = preg_replace_callback(
+							'/\.([a-zA-Z0-9_-]+)/',
+							function( $matches ) use ( $selector, &$selectors_parsed ) {
+								$selectors_parsed[ $selector ]['classes'][] = $matches[1];
+								return '';
+							},
+							$reduced_selector
+						);
+						$reduced_selector = preg_replace_callback(
+							'/#([a-zA-Z0-9_-]+)/',
+							function( $matches ) use ( $selector, &$selectors_parsed ) {
+								$selectors_parsed[ $selector ]['ids'][] = $matches[1];
+								return '';
+							},
+							$reduced_selector
+						);
+
+						if ( preg_match_all( '/[a-zA-Z0-9_-]+/', $reduced_selector, $matches ) ) {
+							$selectors_parsed[ $selector ]['tags'] = $matches[0];
+						}
+					}
+
+					$stylesheet[] = array(
+						$selectors_parsed,
+						$declaration,
+					);
+				} else {
+					$stylesheet[] = $split_stylesheet[ $i ];
+				}
+			}
+		}
+
+		$this->parse_css_duration += ( microtime( true ) - $start_time );
+
+		return array_merge(
+			compact( 'stylesheet', 'validation_results' ),
+			array(
+				'imported_font_urls' => $parsed_stylesheet['imported_font_urls'],
+			)
+		);
+	}
+
+	/**
+	 * Previous return values from calls to should_sanitize_validation_error().
+	 *
+	 * This is used to prevent duplicates from being reported when the sanitization status
+	 * changes for a validation error in a previously-cached stylesheet.
+	 *
+	 * @see AMP_Style_Sanitizer::should_sanitize_validation_error()
+	 * @var array
+	 */
+	protected $previous_should_sanitize_validation_error_results = array();
+
+	/**
+	 * Check whether or not sanitization should occur in response to validation error.
+	 *
+	 * Supply sources to the error and the current node to data.
+	 *
+	 * @since 1.0
+	 *
+	 * @param array $validation_error Validation error.
+	 * @param array $data Data including the node.
+	 * @return bool Whether to sanitize.
+	 */
+	public function should_sanitize_validation_error( $validation_error, $data = array() ) {
+		if ( ! isset( $data['node'] ) ) {
+			$data['node'] = $this->current_node;
+		}
+		if ( ! isset( $validation_error['sources'] ) ) {
+			$validation_error['sources'] = $this->current_sources;
+		}
+
+		/*
+		 * This is used to prevent duplicates from being reported when the sanitization status
+		 * changes for a validation error in a previously-cached stylesheet.
+		 */
+		$args = compact( 'validation_error', 'data' );
+		foreach ( $this->previous_should_sanitize_validation_error_results as $result ) {
+			if ( $result['args'] === $args ) {
+				return $result['sanitized'];
+			}
+		}
+
+		$sanitized = parent::should_sanitize_validation_error( $validation_error, $data );
+
+		$this->previous_should_sanitize_validation_error_results[] = compact( 'args', 'sanitized' );
+		return $sanitized;
+	}
+
+	/**
+	 * Remove spaces from data URLs which PHP-CSS-Parser doesn't handle.
+	 *
+	 * @since 1.0
+	 *
+	 * @param string $css CSS.
+	 * @return string CSS with spaces removed from data URLs.
+	 */
+	private function remove_spaces_from_data_urls( $css ) {
+		return preg_replace_callback(
+			'/\burl\([^}]*?\)/',
+			function( $matches ) {
+				return preg_replace( '/\s+/', '', $matches[0] );
+			},
+			$css
+		);
+	}
+
+	/**
+	 * Process CSS list.
+	 *
+	 * @since 1.0
+	 *
+	 * @param CSSList $css_list CSS List.
+	 * @param array   $options Options.
+	 * @return array Validation errors.
+	 */
+	private function process_css_list( CSSList $css_list, $options ) {
+		$results = array();
+
+		foreach ( $css_list->getContents() as $css_item ) {
+			$sanitized = false;
+			if ( $css_item instanceof DeclarationBlock && empty( $options['validate_keyframes'] ) ) {
+				$results = array_merge(
+					$results,
+					$this->process_css_declaration_block( $css_item, $css_list, $options )
+				);
+			} elseif ( $css_item instanceof AtRuleBlockList ) {
+				if ( ! in_array( $css_item->atRuleName(), $options['allowed_at_rules'], true ) ) {
+					$error     = array(
+						'code'    => self::ILLEGAL_AT_RULE_ERROR_CODE,
+						'at_rule' => $css_item->atRuleName(),
+						'type'    => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
+					);
+					$sanitized = $this->should_sanitize_validation_error( $error );
+					$results[] = compact( 'error', 'sanitized' );
+				}
+				if ( ! $sanitized ) {
+					$results = array_merge(
+						$results,
+						$this->process_css_list( $css_item, $options )
+					);
+				}
+			} elseif ( $css_item instanceof Import ) {
+				$results = array_merge(
+					$results,
+					$this->parse_import_stylesheet( $css_item, $css_list, $options )
+				);
+			} elseif ( $css_item instanceof AtRuleSet ) {
+				if ( ! in_array( $css_item->atRuleName(), $options['allowed_at_rules'], true ) ) {
+					$error     = array(
+						'code'    => self::ILLEGAL_AT_RULE_ERROR_CODE,
+						'at_rule' => $css_item->atRuleName(),
+						'type'    => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
+					);
+					$sanitized = $this->should_sanitize_validation_error( $error );
+					$results[] = compact( 'error', 'sanitized' );
+				}
+
+				if ( ! $sanitized ) {
+					$results = array_merge(
+						$results,
+						$this->process_css_declaration_block( $css_item, $css_list, $options )
+					);
+				}
+			} elseif ( $css_item instanceof KeyFrame ) {
+				if ( ! in_array( 'keyframes', $options['allowed_at_rules'], true ) ) {
+					$error     = array(
+						'code'    => self::ILLEGAL_AT_RULE_ERROR_CODE,
+						'at_rule' => $css_item->atRuleName(),
+						'type'    => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
+					);
+					$sanitized = $this->should_sanitize_validation_error( $error );
+					$results[] = compact( 'error', 'sanitized' );
+				}
+
+				if ( ! $sanitized ) {
+					$results = array_merge(
+						$results,
+						$this->process_css_keyframes( $css_item, $options )
+					);
+				}
+			} elseif ( $css_item instanceof AtRule ) {
+				if ( 'charset' === $css_item->atRuleName() ) {
+					/*
+					 * The @charset at-rule is not allowed in style elements, so it is not allowed in AMP.
+					 * If the @charset is defined, then it really should have already been acknowledged
+					 * by PHP-CSS-Parser when the CSS was parsed in the first place, so at this point
+					 * it is irrelevant and can be removed.
+					 */
+					$sanitized = true;
+				} else {
+					$error     = array(
+						'code'    => self::ILLEGAL_AT_RULE_ERROR_CODE,
+						'at_rule' => $css_item->atRuleName(),
+						'type'    => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
+					);
+					$sanitized = $this->should_sanitize_validation_error( $error );
+					$results[] = compact( 'error', 'sanitized' );
+				}
+			} else {
+				$error     = array(
+					'code' => 'unrecognized_css',
+					'item' => get_class( $css_item ),
+					'type' => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
+				);
+				$sanitized = $this->should_sanitize_validation_error( $error );
+				$results[] = compact( 'error', 'sanitized' );
+			}
+
+			if ( $sanitized ) {
+				$css_list->remove( $css_item );
+			}
+		}
+		return $results;
+	}
+
+	/**
+	 * Convert URLs in to non-relative real-paths.
+	 *
+	 * @param URL[]  $urls           URLs.
+	 * @param string $stylesheet_url Stylesheet URL.
+	 */
+	private function real_path_urls( $urls, $stylesheet_url ) {
+		$base_url = preg_replace( ':[^/]+(\?.*)?(#.*)?$:', '', $stylesheet_url );
+		if ( empty( $base_url ) ) {
+			return;
+		}
+
+		foreach ( $urls as $url ) {
+			// URLs cannot have spaces in them, so strip them (especially when spaces get erroneously injected in data: URLs).
+			$url_string = $url->getURL()->getString();
+
+			// For data: URLs, all that is needed is to remove spaces so set and continue.
+			if ( 'data:' === substr( $url_string, 0, 5 ) ) {
+				continue;
+			}
+
+			// If the URL is already absolute, continue since there there is nothing left to do.
+			$parsed_url = wp_parse_url( $url_string );
+			if ( ! empty( $parsed_url['host'] ) || empty( $parsed_url['path'] ) || '/' === substr( $parsed_url['path'], 0, 1 ) ) {
+				continue;
+			}
+
+			$relative_url = preg_replace( '#^\./#', '', $url->getURL()->getString() );
+
+			// Resolve any relative parent directory paths.
+			$real_url = $base_url . $relative_url;
+			do {
+				$real_url = preg_replace( '#[^/]+/../#', '', $real_url, -1, $count );
+			} while ( 0 !== $count );
+
+			$url->getURL()->setString( $real_url );
+		}
+	}
+
+	/**
+	 * Process CSS rule set.
+	 *
+	 * @since 1.0
+	 * @link https://www.ampproject.org/docs/design/responsive/style_pages#disallowed-styles
+	 * @link https://www.ampproject.org/docs/design/responsive/style_pages#restricted-styles
+	 *
+	 * @param RuleSet $ruleset  Ruleset.
+	 * @param CSSList $css_list CSS List.
+	 * @param array   $options  Options.
+	 *
+	 * @return array Validation results.
+	 */
+	private function process_css_declaration_block( RuleSet $ruleset, CSSList $css_list, $options ) {
+		$results = array();
+
+		if ( $ruleset instanceof DeclarationBlock ) {
+			$this->ampify_ruleset_selectors( $ruleset );
+			if ( 0 === count( $ruleset->getSelectors() ) ) {
+				$css_list->remove( $ruleset );
+				return $results;
+			}
+		}
+
+		// Remove disallowed properties.
+		if ( ! empty( $options['property_whitelist'] ) ) {
+			$properties = $ruleset->getRules();
+			foreach ( $properties as $property ) {
+				$vendorless_property_name = preg_replace( '/^-\w+-/', '', $property->getRule() );
+				if ( ! in_array( $vendorless_property_name, $options['property_whitelist'], true ) ) {
+					$error     = array(
+						'code'           => 'illegal_css_property',
+						'property_name'  => $property->getRule(),
+						'property_value' => $property->getValue(),
+						'type'           => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
+					);
+					$sanitized = $this->should_sanitize_validation_error( $error );
+					if ( $sanitized ) {
+						$ruleset->removeRule( $property->getRule() );
+					}
+					$results[] = compact( 'error', 'sanitized' );
+				}
+			}
+		} else {
+			foreach ( $options['property_blacklist'] as $illegal_property_name ) {
+				$properties = $ruleset->getRules( $illegal_property_name );
+				foreach ( $properties as $property ) {
+					$error     = array(
+						'code'           => 'illegal_css_property',
+						'property_name'  => $property->getRule(),
+						'property_value' => (string) $property->getValue(),
+						'type'           => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
+					);
+					$sanitized = $this->should_sanitize_validation_error( $error );
+					if ( $sanitized ) {
+						$ruleset->removeRule( $property->getRule() );
+					}
+					$results[] = compact( 'error', 'sanitized' );
+				}
+			}
+		}
+
+		if ( $ruleset instanceof AtRuleSet && 'font-face' === $ruleset->atRuleName() ) {
+			$this->process_font_face_at_rule( $ruleset );
+		}
+
+		$results = array_merge(
+			$results,
+			$this->transform_important_qualifiers( $ruleset, $css_list )
+		);
+
+		// Remove the ruleset if it is now empty.
+		if ( 0 === count( $ruleset->getRules() ) ) {
+			$css_list->remove( $ruleset );
+		}
+		// @todo Delete rules with selectors for -amphtml- class and i-amphtml- tags.
+		return $results;
+	}
+
+	/**
+	 * Process @font-face by making src URLs non-relative and converting data: URLs into (assumed) file URLs.
+	 *
+	 * @since 1.0
+	 *
+	 * @param AtRuleSet $ruleset Ruleset for @font-face.
+	 */
+	private function process_font_face_at_rule( AtRuleSet $ruleset ) {
+		$src_properties = $ruleset->getRules( 'src' );
+		if ( empty( $src_properties ) ) {
+			return;
+		}
+
+		foreach ( $src_properties as $src_property ) {
+			$value = $src_property->getValue();
+			if ( ! ( $value instanceof RuleValueList ) ) {
+				continue;
+			}
+
+			/*
+			 * The CSS Parser parses a src such as:
+			 *
+			 *    url(data:application/font-woff;...) format('woff'),
+			 *    url('Genericons.ttf') format('truetype'),
+			 *    url('Genericons.svg#genericonsregular') format('svg')
+			 *
+			 * As a list of components consisting of:
+			 *
+			 *    URL,
+			 *    RuleValueList( CSSFunction, URL ),
+			 *    RuleValueList( CSSFunction, URL ),
+			 *    CSSFunction
+			 *
+			 * Clearly the components here are not logically grouped. So the first step is to fix the order.
+			 */
+			$sources = array();
+			foreach ( $value->getListComponents() as $component ) {
+				if ( $component instanceof RuleValueList ) {
+					$subcomponents = $component->getListComponents();
+					$subcomponent  = array_shift( $subcomponents );
+					if ( $subcomponent ) {
+						if ( empty( $sources ) ) {
+							$sources[] = array( $subcomponent );
+						} else {
+							$sources[ count( $sources ) - 1 ][] = $subcomponent;
+						}
+					}
+					foreach ( $subcomponents as $subcomponent ) {
+						$sources[] = array( $subcomponent );
+					}
+				} else {
+					if ( empty( $sources ) ) {
+						$sources[] = array( $component );
+					} else {
+						$sources[ count( $sources ) - 1 ][] = $component;
+					}
+				}
+			}
+
+			/**
+			 * Source URL lists.
+			 *
+			 * @var URL[] $source_file_urls
+			 * @var URL[] $source_data_urls
+			 */
+			$source_file_urls = array();
+			$source_data_urls = array();
+			foreach ( $sources as $i => $source ) {
+				if ( $source[0] instanceof URL ) {
+					if ( 'data:' === substr( $source[0]->getURL()->getString(), 0, 5 ) ) {
+						$source_data_urls[ $i ] = $source[0];
+					} else {
+						$source_file_urls[ $i ] = $source[0];
+					}
+				}
+			}
+
+			// Convert data: URLs into regular URLs, assuming there will be a file present (e.g. woff fonts in core themes).
+			if ( empty( $source_file_urls ) ) {
+				continue;
+			}
+			$source_file_url = current( $source_file_urls );
+			foreach ( $source_data_urls as $i => $data_url ) {
+				$mime_type = strtok( substr( $data_url->getURL()->getString(), 5 ), ';' );
+				if ( ! $mime_type ) {
+					continue;
+				}
+				$extension   = preg_replace( ':.+/(.+-)?:', '', $mime_type );
+				$guessed_url = preg_replace(
+					':(?<=\.)\w+(\?.*)?(#.*)?$:', // Match the file extension in the URL.
+					$extension,
+					$source_file_url->getURL()->getString(),
+					1,
+					$count
+				);
+				if ( 1 !== $count ) {
+					continue;
+				}
+
+				// Ensure font file exists.
+				$path = $this->get_validated_url_file_path( $guessed_url, array( 'woff', 'woff2', 'ttf', 'otf', 'svg' ) );
+				if ( is_wp_error( $path ) ) {
+					continue;
+				}
+
+				$data_url->getURL()->setString( $guessed_url );
+				break;
+			}
+		}
+	}
+
+	/**
+	 * Process CSS keyframes.
+	 *
+	 * @since 1.0
+	 * @link https://www.ampproject.org/docs/design/responsive/style_pages#restricted-styles.
+	 * @link https://github.com/ampproject/amphtml/blob/b685a0780a7f59313666225478b2b79b463bcd0b/validator/validator-main.protoascii#L1002-L1043
+	 * @todo Tree shaking could be extended to keyframes, to omit a keyframe if it is not referenced by any rule.
+	 *
+	 * @param KeyFrame $css_list Ruleset.
+	 * @param array    $options  Options.
+	 * @return array Validation results.
+	 */
+	private function process_css_keyframes( KeyFrame $css_list, $options ) {
+		$results = array();
+		if ( ! empty( $options['property_whitelist'] ) ) {
+			foreach ( $css_list->getContents() as $rules ) {
+				if ( ! ( $rules instanceof DeclarationBlock ) ) {
+					$error     = array(
+						'code' => 'unrecognized_css',
+						'item' => get_class( $rules ),
+						'type' => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
+					);
+					$sanitized = $this->should_sanitize_validation_error( $error );
+					if ( $sanitized ) {
+						$css_list->remove( $rules );
+					}
+					$results[] = compact( 'error', 'sanitized' );
+					continue;
+				}
+
+				$results = array_merge(
+					$results,
+					$this->transform_important_qualifiers( $rules, $css_list )
+				);
+
+				$properties = $rules->getRules();
+				foreach ( $properties as $property ) {
+					$vendorless_property_name = preg_replace( '/^-\w+-/', '', $property->getRule() );
+					if ( ! in_array( $vendorless_property_name, $options['property_whitelist'], true ) ) {
+						$error     = array(
+							'code'           => 'illegal_css_property',
+							'property_name'  => $property->getRule(),
+							'property_value' => (string) $property->getValue(),
+							'type'           => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
+						);
+						$sanitized = $this->should_sanitize_validation_error( $error );
+						if ( $sanitized ) {
+							$rules->removeRule( $property->getRule() );
+						}
+						$results[] = compact( 'error', 'sanitized' );
+					}
+				}
+			}
+		}
+		return $results;
+	}
+
+	/**
+	 * Replace !important qualifiers with more specific rules.
+	 *
+	 * @since 1.0
+	 * @see https://www.npmjs.com/package/replace-important
+	 * @see https://www.ampproject.org/docs/fundamentals/spec#important
+	 *
+	 * @param RuleSet|DeclarationBlock $ruleset  Rule set.
+	 * @param CSSList                  $css_list CSS List.
+	 * @return array Validation results.
+	 */
+	private function transform_important_qualifiers( RuleSet $ruleset, CSSList $css_list ) {
+		$results = array();
+
+		// An !important only makes sense for rulesets that have selectors.
+		$allow_transformation = (
+			$ruleset instanceof DeclarationBlock
+			&&
+			! ( $css_list instanceof KeyFrame )
+		);
+
+		$properties = $ruleset->getRules();
+		$importants = array();
+		foreach ( $properties as $property ) {
+			if ( $property->getIsImportant() ) {
+				if ( $allow_transformation ) {
+					$importants[] = $property;
+					$property->setIsImportant( false );
+					$ruleset->removeRule( $property->getRule() );
+				} else {
+					$error     = array(
+						'code' => 'illegal_css_important',
+						'type' => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
+					);
+					$sanitized = $this->should_sanitize_validation_error( $error );
+					if ( $sanitized ) {
+						$property->setIsImportant( false );
+					}
+					$results[] = compact( 'error', 'sanitized' );
+				}
+			}
+		}
+		if ( ! $allow_transformation || empty( $importants ) ) {
+			return $results;
+		}
+
+		$important_ruleset = clone $ruleset;
+		$important_ruleset->setSelectors( array_map(
+			/**
+			 * Modify selectors to be more specific to roughly match the effect of !important.
+			 *
+			 * @link https://github.com/ampproject/ampstart/blob/4c21d69afdd07b4c60cd190937bda09901955829/tools/replace-important/lib/index.js#L88-L109
+			 *
+			 * @param Selector $old_selector Original selector.
+			 * @return Selector The new more-specific selector.
+			 */
+			function( Selector $old_selector ) {
+				// Calculate the specificity multiplier for the placeholder.
+				$specificity_multiplier = AMP_Style_Sanitizer::INLINE_SPECIFICITY_MULTIPLIER + 1 + floor( $old_selector->getSpecificity() / 100 );
+				if ( $old_selector->getSpecificity() % 100 > 0 ) {
+					$specificity_multiplier++;
+				}
+				if ( $old_selector->getSpecificity() % 10 > 0 ) {
+					$specificity_multiplier++;
+				}
+				$selector_mod = str_repeat( ':not(#_)', $specificity_multiplier ); // Here "_" is just a short single-char ID.
+
+				$new_selector = $old_selector->getSelector();
+
+				// Amend the selector mod to the first element in selector if it is already the root; otherwise add new root ancestor.
+				if ( preg_match( '/^\s*(html|:root)\b/i', $new_selector, $matches ) ) {
+					$new_selector = substr( $new_selector, 0, strlen( $matches[0] ) ) . $selector_mod . substr( $new_selector, strlen( $matches[0] ) );
+				} else {
+					$new_selector = sprintf( ':root%s %s', $selector_mod, $new_selector );
+				}
+				return new Selector( $new_selector );
+			},
+			$ruleset->getSelectors()
+		) );
+		$important_ruleset->setRules( $importants );
+
+		$i = array_search( $ruleset, $css_list->getContents(), true );
+		if ( false !== $i ) {
+			$css_list->splice( $i + 1, 0, array( $important_ruleset ) );
+		} else {
+			$css_list->append( $important_ruleset );
+		}
+
+		return $results;
+	}
+
+	/**
+	 * Collect and store all CSS style attributes.
+	 *
+	 * Collects the CSS styles from within the HTML contained in this instance's DOMDocument.
+	 *
+	 * @see Retrieve array of styles using $this->get_styles() after calling this method.
+	 *
+	 * @since 0.4
+	 * @since 0.7 Modified to use element passed by XPath query.
+	 *
+	 * @note Uses recursion to traverse down the tree of DOMDocument nodes.
+	 *
+	 * @param DOMElement $element Node.
+	 */
+	private function collect_inline_styles( $element ) {
+		$style_attribute = $element->getAttributeNode( 'style' );
+		if ( ! $style_attribute || ! trim( $style_attribute->nodeValue ) ) {
+			return;
+		}
+
+		$class = 'amp-wp-' . substr( md5( $style_attribute->nodeValue ), 0, 7 );
+		$root  = ':root' . str_repeat( ':not(#_)', self::INLINE_SPECIFICITY_MULTIPLIER );
+		$rule  = sprintf( '%s .%s { %s }', $root, $class, $style_attribute->nodeValue );
+
+		$this->set_current_node( $element ); // And sources when needing to be located.
+
+		$processed = $this->process_stylesheet( $rule, array(
+			'allowed_at_rules'   => array(),
+			'property_whitelist' => $this->style_custom_cdata_spec['css_spec']['declaration'],
+		) );
+
+		$element->removeAttribute( 'style' );
+
+		if ( $processed['stylesheet'] ) {
+			$this->pending_stylesheets[] = array(
+				'stylesheet' => $processed['stylesheet'],
+				'node'       => $element,
+				'sources'    => $this->current_sources,
+			);
+
+			if ( $element->hasAttribute( 'class' ) ) {
+				$element->setAttribute( 'class', $element->getAttribute( 'class' ) . ' ' . $class );
+			} else {
+				$element->setAttribute( 'class', $class );
+			}
+		}
+
+		$this->set_current_node( null );
+	}
+
+	/**
+	 * Finalize stylesheets for style[amp-custom] and style[amp-keyframes] elements.
+	 *
+	 * Concatenate all pending stylesheets, remove unused rules if necessary, and add to style elements in doc.
+	 * Combine all amp-keyframe styles and add them to the end of the body.
+	 *
+	 * @since 1.0
+	 * @see https://www.ampproject.org/docs/fundamentals/spec#keyframes-stylesheet
+	 */
+	private function finalize_styles() {
+
+		$stylesheet_sets = array(
+			'custom'    => array(
+				'source_map_comment'  => "\n\n/*# sourceURL=amp-custom.css */",
+				'total_size'          => 0,
+				'cdata_spec'          => $this->style_custom_cdata_spec,
+				'pending_stylesheets' => array(),
+				'final_stylesheets'   => array(),
+				'remove_unused_rules' => $this->args['remove_unused_rules'],
+			),
+			'keyframes' => array(
+				'source_map_comment'  => "\n\n/*# sourceURL=amp-keyframes.css */",
+				'total_size'          => 0,
+				'cdata_spec'          => $this->style_keyframes_cdata_spec,
+				'pending_stylesheets' => array(),
+				'final_stylesheets'   => array(),
+				'remove_unused_rules' => 'never', // Not relevant.
+			),
+		);
+
+		$imported_font_urls = array();
+
+		/*
+		 * On Native AMP themes when there are new/rejected validation errors present, a parsed stylesheet may include
+		 * @import rules. These must be moved to the beginning to be honored.
+		 */
+		$imports = array();
+
+		// Divide pending stylesheet between custom and keyframes, and calculate size of each.
+		while ( ! empty( $this->pending_stylesheets ) ) {
+			$pending_stylesheet = array_shift( $this->pending_stylesheets );
+
+			$set_name = ! empty( $pending_stylesheet['keyframes'] ) ? 'keyframes' : 'custom';
+			$size     = 0;
+			foreach ( $pending_stylesheet['stylesheet'] as $i => $part ) {
+				if ( is_string( $part ) ) {
+					$size += strlen( $part );
+					if ( '@import' === substr( $part, 0, 7 ) ) {
+						$imports[] = $part;
+						unset( $pending_stylesheet['stylesheet'][ $i ] );
+					}
+				} elseif ( is_array( $part ) ) {
+					$size += strlen( implode( ',', array_keys( $part[0] ) ) ); // Selectors.
+					$size += strlen( $part[1] ); // Declaration block.
+				}
+			}
+			$stylesheet_sets[ $set_name ]['total_size']           += $size;
+			$stylesheet_sets[ $set_name ]['imports']               = $imports;
+			$stylesheet_sets[ $set_name ]['pending_stylesheets'][] = $pending_stylesheet;
+
+			if ( ! empty( $pending_stylesheet['imported_font_urls'] ) ) {
+				$imported_font_urls = array_merge( $imported_font_urls, $pending_stylesheet['imported_font_urls'] );
+			}
+		}
+
+		// Process the pending stylesheets.
+		foreach ( array_keys( $stylesheet_sets ) as $set_name ) {
+			$stylesheet_sets[ $set_name ] = $this->finalize_stylesheet_set( $stylesheet_sets[ $set_name ] );
+		}
+
+		$this->stylesheets = $stylesheet_sets['custom']['final_stylesheets'];
+
+		// If we're not working with the document element (e.g. for legacy post templates) then there is nothing left to do.
+		if ( empty( $this->args['use_document_element'] ) ) {
+			return;
+		}
+
+		// Add style[amp-custom] to document.
+		if ( ! empty( $stylesheet_sets['custom']['final_stylesheets'] ) ) {
+
+			// Ensure style[amp-custom] is present in the document.
+			if ( ! $this->amp_custom_style_element ) {
+				$this->amp_custom_style_element = $this->dom->createElement( 'style' );
+				$this->amp_custom_style_element->setAttribute( 'amp-custom', '' );
+				$this->head->appendChild( $this->amp_custom_style_element );
+			}
+
+			$css  = implode( '', $stylesheet_sets['custom']['imports'] ); // For native dirty AMP.
+			$css .= implode( '', $stylesheet_sets['custom']['final_stylesheets'] );
+			$css .= $stylesheet_sets['custom']['source_map_comment'];
+
+			/*
+			 * Let the style[amp-custom] be populated with the concatenated CSS.
+			 * !important: Updating the contents of this style element by setting textContent is not
+			 * reliable across PHP/libxml versions, so this is why the children are removed and the
+			 * text node is then explicitly added containing the CSS.
+			 */
+			while ( $this->amp_custom_style_element->firstChild ) {
+				$this->amp_custom_style_element->removeChild( $this->amp_custom_style_element->firstChild );
+			}
+			$this->amp_custom_style_element->appendChild( $this->dom->createTextNode( $css ) );
+
+			$included_size          = 0;
+			$included_original_size = 0;
+			$excluded_size          = 0;
+			$excluded_original_size = 0;
+			$included_sources       = array();
+			foreach ( $stylesheet_sets['custom']['pending_stylesheets'] as $i => $pending_stylesheet ) {
+				if ( ! ( $pending_stylesheet['node'] instanceof DOMElement ) ) {
+					continue;
+				}
+				$message = sprintf( '% 6d B', $pending_stylesheet['size'] );
+				if ( $pending_stylesheet['size'] && $pending_stylesheet['size'] !== $pending_stylesheet['original_size'] ) {
+					$message .= sprintf( ' (%d%%)', $pending_stylesheet['size'] / $pending_stylesheet['original_size'] * 100 );
+				}
+				$message .= ': ';
+				$message .= $pending_stylesheet['node']->nodeName;
+				if ( $pending_stylesheet['node']->getAttribute( 'id' ) ) {
+					$message .= '#' . $pending_stylesheet['node']->getAttribute( 'id' );
+				}
+				if ( $pending_stylesheet['node']->getAttribute( 'class' ) ) {
+					$message .= '.' . $pending_stylesheet['node']->getAttribute( 'class' );
+				}
+				foreach ( $pending_stylesheet['node']->attributes as $attribute ) {
+					if ( 'id' !== $attribute->nodeName || 'class' !== $attribute->nodeName ) {
+						$message .= sprintf( '[%s=%s]', $attribute->nodeName, $attribute->nodeValue );
+					}
+				}
+
+				if ( ! empty( $pending_stylesheet['included'] ) ) {
+					$included_sources[]      = $message;
+					$included_size          += $pending_stylesheet['size'];
+					$included_original_size += $pending_stylesheet['original_size'];
+				} else {
+					$excluded_sources[]      = $message;
+					$excluded_size          += $pending_stylesheet['size'];
+					$excluded_original_size += $pending_stylesheet['original_size'];
+				}
+			}
+			$comment = '';
+			if ( ! empty( $included_sources ) && $included_original_size > 0 ) {
+				$comment .= esc_html__( 'The style[amp-custom] element is populated with:', 'amp' ) . "\n" . implode( "\n", $included_sources ) . "\n";
+				$comment .= sprintf(
+					/* translators: %1$d is number of included bytes, %2$d is percentage of total CSS actually included after tree shaking, %3$d is total included size */
+					esc_html__( 'Total included size: %1$s bytes (%2$d%% of %3$s total after tree shaking)', 'amp' ),
+					number_format_i18n( $included_size ),
+					$included_size / $included_original_size * 100,
+					number_format_i18n( $included_original_size )
+				) . "\n";
+			}
+			if ( ! empty( $excluded_sources ) && $excluded_original_size > 0 ) {
+				if ( $comment ) {
+					$comment .= "\n";
+				}
+				$comment .= esc_html__( 'The following stylesheets are too large to be included in style[amp-custom]:', 'amp' ) . "\n" . implode( "\n", $excluded_sources ) . "\n";
+
+				$comment .= sprintf(
+					/* translators: %1$d is number of excluded bytes, %2$d is percentage of total CSS actually excluded even after tree shaking, %3$d is total excluded size */
+					esc_html__( 'Total excluded size: %1$s bytes (%2$d%% of %3$s total after tree shaking)', 'amp' ),
+					number_format_i18n( $excluded_size ),
+					$excluded_size / $excluded_original_size * 100,
+					number_format_i18n( $excluded_original_size )
+				) . "\n";
+
+				$total_size          = $included_size + $excluded_size;
+				$total_original_size = $included_original_size + $excluded_original_size;
+				if ( $total_size !== $total_original_size ) {
+					$comment .= "\n";
+					$comment .= sprintf(
+						/* translators: %1$d is total combined bytes, %2$d is percentage of CSS after tree shaking, %3$d is total before tree shaking */
+						esc_html__( 'Total combined size: %1$s bytes (%2$d%% of %3$s total after tree shaking)', 'amp' ),
+						number_format_i18n( $total_size ),
+						( $total_size / $total_original_size ) * 100,
+						number_format_i18n( $total_original_size )
+					) . "\n";
+				}
+			}
+
+			if ( $comment ) {
+				$this->amp_custom_style_element->parentNode->insertBefore(
+					$this->dom->createComment( "\n$comment" ),
+					$this->amp_custom_style_element
+				);
+			}
+		}
+
+		/*
+		 * Add font stylesheets from CDNs which were extracted from @import rules.
+		 * We can't add crossorigin=anonymous to these since such a CORS request would not be made in the non-AMP version,
+		 * and so if the service worker cached the opaque response on the non-AMP version then it wouldn't be usable in
+		 * the AMP version if it was requested with CORS.
+		 */
+		foreach ( array_unique( $imported_font_urls ) as $imported_font_url ) {
+			$link = $this->dom->createElement( 'link' );
+			$link->setAttribute( 'rel', 'stylesheet' );
+			$link->setAttribute( 'href', $imported_font_url );
+			$this->head->appendChild( $link );
+		}
+
+		// Add style[amp-keyframes] to document.
+		if ( ! empty( $stylesheet_sets['keyframes']['final_stylesheets'] ) ) {
+			$body = $this->dom->getElementsByTagName( 'body' )->item( 0 );
+			if ( ! $body ) {
+				$this->should_sanitize_validation_error( array(
+					'code' => 'missing_body_element',
+					'type' => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
+				) );
+			} else {
+				$css  = implode( '', $stylesheet_sets['keyframes']['final_stylesheets'] );
+				$css .= $stylesheet_sets['keyframes']['source_map_comment'];
+
+				$style_element = $this->dom->createElement( 'style' );
+				$style_element->setAttribute( 'amp-keyframes', '' );
+				$style_element->appendChild( $this->dom->createTextNode( $css ) );
+				$body->appendChild( $style_element );
+			}
+		}
+	}
+
+	/**
+	 * Convert CSS selectors and remove obsolete selector hacks for IE.
+	 *
+	 * @param DeclarationBlock $ruleset Ruleset.
+	 */
+	private function ampify_ruleset_selectors( $ruleset ) {
+		$selectors = array();
+		$changes   = 0;
+		$language  = get_bloginfo( 'language' );
+		foreach ( $ruleset->getSelectors() as $old_selector ) {
+			$selector = $old_selector->getSelector();
+
+			// Automatically tree-shake IE6/IE7 hacks for selectors with `* html` and `*+html`.
+			if ( preg_match( '/^\*\s*\+?\s*html/', $selector ) ) {
+				$changes++;
+				continue;
+			}
+
+			// Automatically remove selectors that are for another language (and thus are irrelevant). This is safe because amp-bind'ed [lang] is not allowed.
+			$is_other_language = (
+				preg_match( '/^html\[lang(?P<starts_with>\^?)=([\'"]?)(?P<lang>.+?)\2\]/', $selector, $matches )
+				&&
+				(
+					empty( $matches['starts_with'] )
+					?
+					$language !== $matches['lang']
+					:
+					substr( $language, 0, strlen( $matches['lang'] ) ) !== $matches['lang']
+				)
+			);
+			if ( $is_other_language ) {
+				$changes++;
+				continue;
+			}
+
+			// An element (type) either starts a selector or is preceded by combinator, comma, opening paren, or closing brace.
+			$before_type_selector_pattern = '(?<=^|\(|\s|>|\+|~|,|})';
+			$after_type_selector_pattern  = '(?=$|[^a-zA-Z0-9_-])';
+
+			$edited_selectors = array( $selector );
+			foreach ( $this->selector_mappings as $html_selector => $amp_selectors ) { // Note: The $selector_mappings array contains ~6 items.
+				$html_pattern = '/' . $before_type_selector_pattern . preg_quote( $html_selector, '/' ) . $after_type_selector_pattern . '/i';
+				foreach ( $edited_selectors as &$edited_selector ) { // Note: The $edited_selectors array contains only item in the normal case.
+					$original_selector = $edited_selector;
+					$amp_selector      = array_shift( $amp_selectors );
+					$amp_tag_pattern   = '/' . $before_type_selector_pattern . preg_quote( $amp_selector, '/' ) . $after_type_selector_pattern . '/i';
+					preg_match( $amp_tag_pattern, $edited_selector, $matches );
+					if ( ! empty( $matches ) && $amp_selector === $matches[0] ) {
+						continue;
+					}
+					$edited_selector = preg_replace( $html_pattern, $amp_selector, $edited_selector, -1, $count );
+					if ( ! $count ) {
+						continue;
+					}
+					$changes += $count;
+					while ( ! empty( $amp_selectors ) ) { // Note: This array contains only a couple items.
+						$amp_selector       = array_shift( $amp_selectors );
+						$edited_selectors[] = preg_replace( $html_pattern, $amp_selector, $original_selector, -1, $count );
+					}
+				}
+			}
+			$selectors = array_merge( $selectors, $edited_selectors );
+		}
+
+		if ( $changes > 0 ) {
+			$ruleset->setSelectors( $selectors );
+		}
+	}
+
+	/**
+	 * Finalize a stylesheet set (amp-custom or amp-keyframes).
+	 *
+	 * @since 1.0
+	 *
+	 * @param array $stylesheet_set Stylesheet set.
+	 * @return array Finalized stylesheet set.
+	 */
+	private function finalize_stylesheet_set( $stylesheet_set ) {
+		$max_bytes         = $stylesheet_set['cdata_spec']['max_bytes'] - strlen( $stylesheet_set['source_map_comment'] );
+		$is_too_much_css   = $stylesheet_set['total_size'] > $max_bytes;
+		$should_tree_shake = (
+			'always' === $stylesheet_set['remove_unused_rules'] || (
+				$is_too_much_css
+				&&
+				'sometimes' === $stylesheet_set['remove_unused_rules']
+			)
+		);
+
+		if ( $is_too_much_css && $should_tree_shake && empty( $this->args['accept_tree_shaking'] ) ) {
+			$should_tree_shake = $this->should_sanitize_validation_error( array(
+				'code' => self::TREE_SHAKING_ERROR_CODE,
+				'type' => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
+			) );
+		}
+
+		$stylesheet_set['processed_nodes'] = array();
+
+		$final_size = 0;
+		$dom        = $this->dom;
+		foreach ( $stylesheet_set['pending_stylesheets'] as &$pending_stylesheet ) {
+			$stylesheet_parts = array();
+			$original_size    = 0;
+			foreach ( $pending_stylesheet['stylesheet'] as $stylesheet_part ) {
+				if ( is_string( $stylesheet_part ) ) {
+					$stylesheet_parts[] = $stylesheet_part;
+					$original_size     += strlen( $stylesheet_part );
+					continue;
+				}
+
+				list( $selectors_parsed, $declaration_block ) = $stylesheet_part;
+				if ( $should_tree_shake ) {
+					$selectors = array();
+					foreach ( $selectors_parsed as $selector => $parsed_selector ) {
+						$should_include = (
+							(
+								// If all class names are used in the doc.
+								(
+									empty( $parsed_selector['classes'] )
+									||
+									0 === count( array_diff( $parsed_selector['classes'], $this->get_used_class_names() ) )
+								)
+								&&
+								// If all IDs are used in the doc.
+								(
+									empty( $parsed_selector['ids'] )
+									||
+									0 === count( array_filter( $parsed_selector['ids'], function( $id ) use ( $dom ) {
+										return ! $dom->getElementById( $id );
+									} ) )
+								)
+								&&
+								// If tag names are present in the doc.
+								(
+									empty( $parsed_selector['tags'] )
+									||
+									0 === count( array_diff( $parsed_selector['tags'], $this->get_used_tag_names() ) )
+								)
+							)
+						);
+						if ( $should_include ) {
+							$selectors[] = $selector;
+						}
+					}
+				} else {
+					$selectors = array_keys( $selectors_parsed );
+				}
+				$stylesheet_part = implode( ',', $selectors ) . $declaration_block;
+				$original_size  += strlen( $stylesheet_part );
+				if ( ! empty( $selectors ) ) {
+					$stylesheet_parts[] = $stylesheet_part;
+				}
+			}
+
+			// Strip empty at-rules after tree shaking.
+			$stylesheet_part_count = count( $stylesheet_parts );
+			for ( $i = 0; $i < $stylesheet_part_count; $i++ ) {
+				$stylesheet_part = $stylesheet_parts[ $i ];
+				if ( '@' !== substr( $stylesheet_part, 0, 1 ) ) {
+					continue;
+				}
+
+				// Delete empty at-rules.
+				if ( '{}' === substr( $stylesheet_part, -2 ) ) {
+					$stylesheet_part_count--;
+					array_splice( $stylesheet_parts, $i, 1 );
+					$i--;
+					continue;
+				}
+
+				// Delete at-rules that were emptied due to tree-shaking.
+				if ( '{' === substr( $stylesheet_part, -1 ) ) {
+					$open_braces = 1;
+					for ( $j = $i + 1; $j < $stylesheet_part_count; $j++ ) {
+						$stylesheet_part = $stylesheet_parts[ $j ];
+						$is_at_rule      = '@' === substr( $stylesheet_part, 0, 1 );
+						if ( empty( $stylesheet_part ) ) {
+							continue; // There was a shaken rule.
+						} elseif ( $is_at_rule && '{}' === substr( $stylesheet_part, -2 ) ) {
+							continue; // The rule opens is empty from the start.
+						} elseif ( $is_at_rule && '{' === substr( $stylesheet_part, -1 ) ) {
+							$open_braces++;
+						} elseif ( '}' === $stylesheet_part ) {
+							$open_braces--;
+						} else {
+							break;
+						}
+
+						// Splice out the parts that are empty.
+						if ( 0 === $open_braces ) {
+							array_splice( $stylesheet_parts, $i, $j - $i + 1 );
+							$stylesheet_part_count = count( $stylesheet_parts );
+							$i--;
+							continue 2;
+						}
+					}
+				}
+			}
+			$pending_stylesheet['original_size'] = $original_size;
+
+			$stylesheet = implode( '', $stylesheet_parts );
+			unset( $stylesheet_parts );
+			$sheet_size                 = strlen( $stylesheet );
+			$pending_stylesheet['size'] = $sheet_size;
+
+			// Skip considering stylesheet if an identical one has already been processed.
+			$hash = md5( $stylesheet );
+			if ( isset( $stylesheet_set['final_stylesheets'][ $hash ] ) ) {
+				$pending_stylesheet['included'] = true;
+				continue;
+			}
+
+			// Report validation error if size is now too big.
+			if ( $final_size + $sheet_size > $max_bytes ) {
+				$validation_error = array(
+					'code' => 'excessive_css',
+					'type' => AMP_Validation_Error_Taxonomy::CSS_ERROR_TYPE,
+				);
+				if ( isset( $pending_stylesheet['sources'] ) ) {
+					$validation_error['sources'] = $pending_stylesheet['sources'];
+				}
+
+				if ( $this->should_sanitize_validation_error( $validation_error, wp_array_slice_assoc( $pending_stylesheet, array( 'node' ) ) ) ) {
+					$pending_stylesheet['included'] = false;
+					continue; // Skip to the next stylesheet.
+				}
+			}
+
+			$final_size += $sheet_size;
+
+			$pending_stylesheet['included']               = true;
+			$stylesheet_set['final_stylesheets'][ $hash ] = $stylesheet;
+		}
+
+		return $stylesheet_set;
+	}
+}
diff --git a/includes/sanitizers/class-amp-tag-and-attribute-sanitizer.php b/includes/sanitizers/class-amp-tag-and-attribute-sanitizer.php
new file mode 100644
index 00000000000..0d97a209eca
--- /dev/null
+++ b/includes/sanitizers/class-amp-tag-and-attribute-sanitizer.php
@@ -0,0 +1,1874 @@
+<?php
+/**
+ * Class AMP_Tag_And_Attribute_Sanitizer
+ *
+ * @package AMP
+ */
+
+/**
+ * Strips the tags and attributes from the content that are not allowed by the AMP spec.
+ *
+ * Allowed tags array is generated from this protocol buffer:
+ *
+ *     https://github.com/ampproject/amphtml/blob/master/validator/validator-main.protoascii
+ *     by the python script in amp-wp/bin/amp_wp_build.py. See the comment at the top
+ *     of that file for instructions to generate class-amp-allowed-tags-generated.php.
+ *
+ * @todo Need to check the following items that are not yet checked by this sanitizer:
+ *
+ *     - `also_requires_attr` - if one attribute is present, this requires another.
+ *     - `ChildTagSpec`       - Places restrictions on the number and type of child tags.
+ *     - `if_value_regex`     - if one attribute value matches, this places a restriction
+ *                              on another attribute/value.
+ *     - `mandatory_oneof`    - Within the context of the tag, exactly one of the attributes
+ *                              must be present.
+ */
+class AMP_Tag_And_Attribute_Sanitizer extends AMP_Base_Sanitizer {
+
+	/**
+	 * Allowed tags.
+	 *
+	 * @since 0.5
+	 *
+	 * @var string[]
+	 */
+	protected $allowed_tags;
+
+	/**
+	 * Globally-allowed attributes.
+	 *
+	 * @since 0.5
+	 *
+	 * @var array[][]
+	 */
+	protected $globally_allowed_attributes;
+
+	/**
+	 * Layout-allowed attributes.
+	 *
+	 * @since 0.5
+	 *
+	 * @var string[]
+	 */
+	protected $layout_allowed_attributes;
+
+	/**
+	 * Mapping of alternative names back to their primary names.
+	 *
+	 * @since 0.7
+	 * @var array
+	 */
+	protected $rev_alternate_attr_name_lookup = array();
+
+	/**
+	 * Stack.
+	 *
+	 * @since 0.5
+	 *
+	 * @var DOMElement[]
+	 */
+	private $stack = array();
+
+	/**
+	 * Default args.
+	 *
+	 * @since 0.5
+	 *
+	 * @var array
+	 */
+	protected $DEFAULT_ARGS = array();
+
+	/**
+	 * AMP script components that are discovered being required through sanitization.
+	 *
+	 * @var string[]
+	 */
+	protected $script_components = array();
+
+	/**
+	 * Keep track of nodes that should not be replaced to prevent duplicated validation errors since sanitization is rejected.
+	 *
+	 * @var array
+	 */
+	protected $should_not_replace_nodes = array();
+
+	/**
+	 * AMP_Tag_And_Attribute_Sanitizer constructor.
+	 *
+	 * @since 0.5
+	 *
+	 * @param DOMDocument $dom  DOM.
+	 * @param array       $args Args.
+	 */
+	public function __construct( $dom, $args = array() ) {
+		$this->DEFAULT_ARGS = array(
+			'amp_allowed_tags'                => AMP_Allowed_Tags_Generated::get_allowed_tags(),
+			'amp_globally_allowed_attributes' => AMP_Allowed_Tags_Generated::get_allowed_attributes(),
+			'amp_layout_allowed_attributes'   => AMP_Allowed_Tags_Generated::get_layout_attributes(),
+			'amp_bind_placeholder_prefix'     => AMP_DOM_Utils::get_amp_bind_placeholder_prefix(),
+		);
+
+		parent::__construct( $dom, $args );
+
+		if ( ! empty( $this->args['allow_dirty_styles'] ) ) {
+
+			// Allow style attribute on all elements.
+			$this->args['amp_globally_allowed_attributes']['style'] = array();
+
+			// Allow style elements.
+			$this->args['amp_allowed_tags']['style'][] = array(
+				'attr_spec_list' => array(
+					'type' => array(
+						'value_casei' => 'text/css',
+					),
+				),
+				'cdata'          => array(),
+				'tag_spec'       => array(
+					'spec_name' => 'style for Customizer preview',
+				),
+			);
+
+			// Allow stylesheet links.
+			$this->args['amp_allowed_tags']['link'][] = array(
+				'attr_spec_list' => array(
+					'async'       => array(),
+					'crossorigin' => array(),
+					'href'        => array(
+						'mandatory' => true,
+					),
+					'integrity'   => array(),
+					'media'       => array(),
+					'rel'         => array(
+						'dispatch_key' => 2,
+						'mandatory'    => true,
+						'value_casei'  => 'stylesheet',
+					),
+					'type'        => array(
+						'value_casei' => 'text/css',
+					),
+				),
+				'tag_spec'       => array(
+					'spec_name' => 'link rel=stylesheet for Customizer preview', // phpcs:ignore WordPress.WP.EnqueuedResources.NonEnqueuedStylesheet
+				),
+			);
+		}
+
+		// Allow scripts if requested.
+		if ( ! empty( $this->args['allow_dirty_scripts'] ) ) {
+			$this->args['amp_allowed_tags']['script'][] = array(
+				'attr_spec_list' => array(
+					'type'  => array(),
+					'src'   => array(),
+					'async' => array(),
+					'defer' => array(),
+				),
+				'cdata'          => array(),
+				'tag_spec'       => array(
+					'spec_name' => 'scripts for Customizer preview',
+				),
+			);
+		}
+
+		// Prepare whitelists.
+		$this->allowed_tags = $this->args['amp_allowed_tags'];
+		foreach ( AMP_Rule_Spec::$additional_allowed_tags as $tag_name => $tag_rule_spec ) {
+			$this->allowed_tags[ $tag_name ][] = $tag_rule_spec;
+		}
+
+		// @todo Do the same for body when !use_document_element?
+		if ( ! empty( $this->args['use_document_element'] ) ) {
+			foreach ( $this->allowed_tags['html'] as &$rule_spec ) {
+				unset( $rule_spec[ AMP_Rule_Spec::TAG_SPEC ][ AMP_Rule_Spec::MANDATORY_PARENT ] );
+			}
+		}
+
+		foreach ( $this->allowed_tags as &$tag_specs ) {
+			foreach ( $tag_specs as &$tag_spec ) {
+				if ( isset( $tag_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ] ) ) {
+					$tag_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ] = $this->process_alternate_names( $tag_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ] );
+				}
+			}
+		}
+		$this->globally_allowed_attributes = $this->process_alternate_names( $this->args['amp_globally_allowed_attributes'] );
+		$this->layout_allowed_attributes   = $this->process_alternate_names( $this->args['amp_layout_allowed_attributes'] );
+	}
+
+	/**
+	 * Return array of values that would be valid as an HTML `script` element.
+	 *
+	 * Array keys are AMP element names and array values are their respective
+	 * Javascript URLs from https://cdn.ampproject.org
+	 *
+	 * @since 0.7
+	 * @see amp_register_default_scripts()
+	 *
+	 * @return array() Returns component name as array key and true as value (or JavaScript URL string),
+	 *                  respectively. When true then the default component script URL will be used.
+	 *                  Will return an empty array if sanitization has yet to be run
+	 *                  or if it did not find any HTML elements to convert to AMP equivalents.
+	 */
+	public function get_scripts() {
+		return array_fill_keys( array_unique( $this->script_components ), true );
+	}
+
+	/**
+	 * Process alternative names in attribute spec list.
+	 *
+	 * @since 0.7
+	 *
+	 * @param array $attr_spec_list Attribute spec list.
+	 * @return array Modified attribute spec list.
+	 */
+	private function process_alternate_names( $attr_spec_list ) {
+		foreach ( $attr_spec_list as $attr_name => &$attr_spec ) {
+			if ( '[' === $attr_name[0] ) {
+				$placeholder_attr_name = $this->args['amp_bind_placeholder_prefix'] . trim( $attr_name, '[]' );
+				if ( ! isset( $attr_spec[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] ) ) {
+					$attr_spec[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] = array();
+				}
+				$attr_spec[ AMP_Rule_Spec::ALTERNATIVE_NAMES ][] = $placeholder_attr_name;
+			}
+
+			// Save all alternative names in lookup to improve performance.
+			if ( isset( $attr_spec[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] ) ) {
+				foreach ( $attr_spec[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] as $alternative_name ) {
+					$this->rev_alternate_attr_name_lookup[ $alternative_name ] = $attr_name;
+				}
+			}
+		}
+		return $attr_spec_list;
+	}
+
+	/**
+	 * Sanitize the elements from the HTML contained in this instance's DOMDocument.
+	 *
+	 * @since 0.5
+	 */
+	public function sanitize() {
+
+		// Add root of content to the stack.
+		$this->stack[] = $this->root_element;
+
+		/**
+		 * This loop traverses through the DOM tree iteratively.
+		 */
+		while ( ! empty( $this->stack ) ) {
+
+			// Get the next node to process.
+			$node = array_shift( $this->stack );
+
+			/**
+			 * Process this node.
+			 */
+			$this->process_node( $node );
+
+			/*
+			 * Push child nodes onto the stack, if any exist.
+			 * if node was removed, then it's parentNode value is null.
+			 */
+			if ( $node->parentNode ) {
+				$child = $node->firstChild;
+				while ( $child ) {
+					$this->stack[] = $child;
+					$child         = $child->nextSibling;
+				}
+			}
+		}
+	}
+
+	/**
+	 * Augment rule spec for validation.
+	 *
+	 * @since 1.0
+	 *
+	 * @param DOMElement $node      Node.
+	 * @param array      $rule_spec Rule spec.
+	 * @return array Augmented rule spec.
+	 */
+	private function get_rule_spec_list_to_validate( $node, $rule_spec ) {
+
+		// Expand extension_spec into a set of attr_spec_list.
+		if ( isset( $rule_spec[ AMP_Rule_Spec::TAG_SPEC ]['extension_spec'] ) ) {
+			$extension_spec = $rule_spec[ AMP_Rule_Spec::TAG_SPEC ]['extension_spec'];
+			$custom_attr    = 'amp-mustache' === $extension_spec['name'] ? 'custom-template' : 'custom-element';
+
+			$rule_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ][ $custom_attr ] = array(
+				AMP_Rule_Spec::VALUE     => $extension_spec['name'],
+				AMP_Rule_Spec::MANDATORY => true,
+			);
+
+			$versions = array_unique( array_merge(
+				isset( $extension_spec['allowed_versions'] ) ? $extension_spec['allowed_versions'] : array(),
+				isset( $extension_spec['version'] ) ? $extension_spec['version'] : array()
+			) );
+
+			$rule_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ]['src'] = array(
+				AMP_Rule_Spec::VALUE_REGEX => implode( '', array(
+					'^',
+					preg_quote( 'https://cdn.ampproject.org/v0/' . $extension_spec['name'] . '-' ),
+					'(' . implode( '|', $versions ) . ')',
+					'\.js$',
+				) ),
+			);
+		}
+
+		// Augment the attribute list according to the parent's reference points, if it has them.
+		if ( ! empty( $node->parentNode ) && isset( $this->allowed_tags[ $node->parentNode->nodeName ] ) ) {
+			foreach ( $this->allowed_tags[ $node->parentNode->nodeName ] as $parent_rule_spec ) {
+				if ( empty( $parent_rule_spec[ AMP_Rule_Spec::TAG_SPEC ]['reference_points'] ) ) {
+					continue;
+				}
+				foreach ( $parent_rule_spec[ AMP_Rule_Spec::TAG_SPEC ]['reference_points'] as $reference_point_spec_name => $reference_point_spec_instance_attrs ) {
+					$reference_point = AMP_Allowed_Tags_Generated::get_reference_point_spec( $reference_point_spec_name );
+					if ( empty( $reference_point[ AMP_Rule_Spec::ATTR_SPEC_LIST ] ) ) {
+						/*
+						 * See special case for amp-selector in AMP_Tag_And_Attribute_Sanitizer::is_amp_allowed_attribute()
+						 * where its reference point applies to any descendant elements, not just direct children.
+						 */
+						continue;
+					}
+					foreach ( $reference_point[ AMP_Rule_Spec::ATTR_SPEC_LIST ] as $attr_name => $reference_point_spec_attr ) {
+						$reference_point_spec_attr = array_merge(
+							$reference_point_spec_attr,
+							$reference_point_spec_instance_attrs
+						);
+
+						/*
+						 * Ignore mandatory constraint for now since this would end up causing other sibling children
+						 * getting removed due to missing a mandatory attribute. To sanitize this it would require
+						 * higher-level processing to look at an element's surrounding context, similar to how the
+						 * sanitizer does not yet handle the mandatory_oneof constraint.
+						 */
+						unset( $reference_point_spec_attr['mandatory'] );
+
+						$rule_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ][ $attr_name ] = $reference_point_spec_attr;
+					}
+				}
+			}
+		}
+		return $rule_spec;
+	}
+
+	/**
+	 * Process a node by checking if an element and its attributes are valid, and removing them when invalid.
+	 *
+	 * Attributes which are not valid are removed. Elements which are not allowed are also removed,
+	 * including elements which miss mandatory attributes.
+	 *
+	 * @param DOMNode $node Node.
+	 */
+	private function process_node( $node ) {
+
+		// Don't process text or comment nodes.
+		if ( XML_TEXT_NODE === $node->nodeType || XML_COMMENT_NODE === $node->nodeType || XML_CDATA_SECTION_NODE === $node->nodeType ) {
+			return;
+		}
+
+		// Remove nodes with tags that have not been whitelisted.
+		if ( ! $this->is_amp_allowed_tag( $node ) ) {
+
+			// If it's not an allowed tag, replace the node with it's children.
+			$this->replace_node_with_children( $node );
+
+			// Return early since this node no longer exists.
+			return;
+		}
+
+		/**
+		 * Node is now an element.
+		 *
+		 * @var DOMElement $node
+		 */
+
+		/*
+		 * Compile a list of rule_specs to validate for this node
+		 * based on tag name of the node.
+		 */
+		$rule_spec_list_to_validate = array();
+		$rule_spec_list             = array();
+		if ( isset( $this->allowed_tags[ $node->nodeName ] ) ) {
+			$rule_spec_list = $this->allowed_tags[ $node->nodeName ];
+		}
+		foreach ( $rule_spec_list as $id => $rule_spec ) {
+			if ( $this->validate_tag_spec_for_node( $node, $rule_spec[ AMP_Rule_Spec::TAG_SPEC ] ) ) {
+				$rule_spec_list_to_validate[ $id ] = $this->get_rule_spec_list_to_validate( $node, $rule_spec );
+			}
+		}
+
+		// If no valid rule_specs exist, then remove this node and return.
+		if ( empty( $rule_spec_list_to_validate ) ) {
+			$this->remove_node( $node );
+			return;
+		}
+
+		// The remaining validations all have to do with attributes.
+		$attr_spec_list = array();
+		$tag_spec       = array();
+		$cdata          = array();
+
+		/*
+		 * If we have exactly one rule_spec, use it's attr_spec_list
+		 * to validate the node's attributes.
+		 */
+		if ( 1 === count( $rule_spec_list_to_validate ) ) {
+			$rule_spec      = array_pop( $rule_spec_list_to_validate );
+			$attr_spec_list = $rule_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ];
+			$tag_spec       = $rule_spec[ AMP_Rule_Spec::TAG_SPEC ];
+			if ( isset( $rule_spec[ AMP_Rule_Spec::CDATA ] ) ) {
+				$cdata = $rule_spec[ AMP_Rule_Spec::CDATA ];
+			}
+		} else {
+			/*
+			 * If there is more than one valid rule_spec for this node,
+			 * then try to deduce which one is intended by inspecting
+			 * the node's attributes.
+			 */
+
+			/*
+			 * Get a score from each attr_spec_list by seeing how many
+			 * attributes and values match the node.
+			 */
+			$attr_spec_scores = array();
+			foreach ( $rule_spec_list_to_validate as $spec_id => $rule_spec ) {
+				$attr_spec_scores[ $spec_id ] = $this->validate_attr_spec_list_for_node( $node, $rule_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ] );
+			}
+
+			// Remove all spec lists that didn't match.
+			$attr_spec_scores = array_filter( $attr_spec_scores );
+
+			// If no attribute spec lists match, then the element must be removed.
+			if ( empty( $attr_spec_scores ) ) {
+				$this->remove_node( $node );
+				return;
+			}
+
+			// Get the key(s) to the highest score(s).
+			$spec_ids_sorted = array_keys( $attr_spec_scores, max( $attr_spec_scores ), true );
+
+			// If there is exactly one attr_spec with a max score, use that one.
+			if ( 1 === count( $spec_ids_sorted ) ) {
+				$attr_spec_list = $rule_spec_list_to_validate[ $spec_ids_sorted[0] ][ AMP_Rule_Spec::ATTR_SPEC_LIST ];
+				$tag_spec       = $rule_spec_list_to_validate[ $spec_ids_sorted[0] ][ AMP_Rule_Spec::TAG_SPEC ];
+				if ( isset( $rule_spec_list_to_validate[ $spec_ids_sorted[0] ][ AMP_Rule_Spec::CDATA ] ) ) {
+					$cdata = $rule_spec_list_to_validate[ $spec_ids_sorted[0] ][ AMP_Rule_Spec::CDATA ];
+				}
+			} else {
+				// This should not happen very often, but...
+				// If we're here, then we're not sure which spec should
+				// be used. Let's use the top scoring ones.
+				foreach ( $spec_ids_sorted as $id ) {
+					$spec_list = isset( $rule_spec_list_to_validate[ $id ][ AMP_Rule_Spec::ATTR_SPEC_LIST ] ) ? $rule_spec_list_to_validate[ $id ][ AMP_Rule_Spec::ATTR_SPEC_LIST ] : null;
+					if ( ! $this->is_missing_mandatory_attribute( $spec_list, $node ) ) {
+						$attr_spec_list = array_merge( $attr_spec_list, $spec_list );
+						$tag_spec       = array_merge(
+							$tag_spec,
+							$rule_spec_list_to_validate[ $id ][ AMP_Rule_Spec::TAG_SPEC ]
+						);
+						if ( isset( $rule_spec_list_to_validate[ $id ][ AMP_Rule_Spec::CDATA ] ) ) {
+							$cdata = array_merge( $cdata, $rule_spec_list_to_validate[ $id ][ AMP_Rule_Spec::CDATA ] );
+						}
+					}
+				}
+				$first_spec = reset( $rule_spec_list_to_validate );
+				if ( empty( $attr_spec_list ) && isset( $first_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ] ) ) {
+					$attr_spec_list = $first_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ];
+				}
+			}
+		}
+
+		if ( ! empty( $attr_spec_list ) && $this->is_missing_mandatory_attribute( $attr_spec_list, $node ) ) {
+			$this->remove_node( $node );
+			return;
+		}
+
+		// Remove element if it has illegal CDATA.
+		if ( ! empty( $cdata ) && $node instanceof DOMElement ) {
+			$validity = $this->validate_cdata_for_node( $node, $cdata );
+			if ( is_wp_error( $validity ) ) {
+				$this->remove_node( $node );
+				return;
+			}
+		}
+
+		$merged_attr_spec_list = array_merge(
+			$this->globally_allowed_attributes,
+			$attr_spec_list
+		);
+
+		// Amend spec list with layout.
+		if ( isset( $tag_spec['amp_layout'] ) ) {
+			$merged_attr_spec_list = array_merge( $merged_attr_spec_list, $this->layout_allowed_attributes );
+
+			if ( isset( $tag_spec['amp_layout']['supported_layouts'] ) ) {
+				$layouts = wp_array_slice_assoc( AMP_Rule_Spec::$layout_enum, $tag_spec['amp_layout']['supported_layouts'] );
+
+				$merged_attr_spec_list['layout'][ AMP_Rule_Spec::VALUE_REGEX_CASEI ] = '(' . implode( '|', $layouts ) . ')';
+			}
+		}
+
+		// Identify any remaining disallowed attributes.
+		$disallowed_attributes = $this->get_disallowed_attributes_in_node( $node, $merged_attr_spec_list );
+
+		// Identify attribute values that don't conform to the attr_spec.
+		$disallowed_attributes = $this->sanitize_disallowed_attribute_values_in_node( $node, $merged_attr_spec_list, $disallowed_attributes );
+
+		// If $disallowed_attributes is false then the entire element should be removed.
+		if ( false === $disallowed_attributes ) {
+			$this->remove_node( $node );
+			return;
+		}
+
+		// Remove all invalid attributes.
+		if ( ! empty( $disallowed_attributes ) ) {
+			/*
+			 * Capture all element attributes up front so that differing validation errors result when
+			 * one invalid attribute is accepted but the others are still rejected.
+			 */
+			$validation_error = array(
+				'element_attributes' => array(),
+			);
+			foreach ( $node->attributes as $attribute ) {
+				$validation_error['element_attributes'][ $attribute->nodeName ] = $attribute->nodeValue;
+			}
+			foreach ( $disallowed_attributes as $disallowed_attribute ) {
+				$this->remove_invalid_attribute( $node, $disallowed_attribute, $validation_error );
+			}
+		}
+
+		// Add required AMP component scripts if the element is still in the document.
+		if ( $node->parentNode ) {
+			if ( ! empty( $tag_spec['also_requires_tag_warning'] ) ) {
+				$this->script_components[] = strtok( $tag_spec['also_requires_tag_warning'][0], ' ' );
+			}
+			if ( ! empty( $tag_spec['requires_extension'] ) ) {
+				$this->script_components = array_merge( $this->script_components, $tag_spec['requires_extension'] );
+			}
+
+			// Check if element needs amp-bind component.
+			if ( $node instanceof DOMElement && ! in_array( 'amp-bind', $this->script_components, true ) ) {
+				foreach ( $node->attributes as $name => $value ) {
+					$is_bind_attribute = (
+						'[' === $name[0]
+						||
+						( isset( $this->rev_alternate_attr_name_lookup[ $name ] ) && '[' === $this->rev_alternate_attr_name_lookup[ $name ][0] )
+					);
+					if ( $is_bind_attribute ) {
+						$this->script_components[] = 'amp-bind';
+						break;
+					}
+				}
+			}
+		}
+	}
+
+	/**
+	 * Whether a node is missing a mandatory attribute.
+	 *
+	 * @param array      $attr_spec The attribute specification.
+	 * @param DOMElement $node      The DOMElement of the node to check.
+	 * @return boolean $is_missing boolean Whether a required attribute is missing.
+	 */
+	public function is_missing_mandatory_attribute( $attr_spec, $node ) {
+		if ( ! is_array( $attr_spec ) ) {
+			return false;
+		}
+		foreach ( $attr_spec as $attr_name => $attr_spec_rule_value ) {
+			if ( '\u' === substr( $attr_name, 0, 2 ) ) {
+				$attr_name = html_entity_decode( '&#x' . substr( $attr_name, 2 ) . ';' ); // Probably ⚡.
+			}
+			$is_mandatory     = isset( $attr_spec_rule_value[ AMP_Rule_Spec::MANDATORY ] ) ? ( true === $attr_spec_rule_value[ AMP_Rule_Spec::MANDATORY ] ) : false;
+			$attribute_exists = false;
+			if ( method_exists( $node, 'hasAttribute' ) ) {
+				$attribute_exists = $node->hasAttribute( $attr_name );
+				if ( ! $attribute_exists && ! empty( $attr_spec_rule_value[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] ) ) {
+					foreach ( $attr_spec_rule_value[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] as $alternative_attr_name ) {
+						if ( $node->hasAttribute( $alternative_attr_name ) ) {
+							$attribute_exists = true;
+							break;
+						}
+					}
+				}
+			}
+			if ( $is_mandatory && ! $attribute_exists ) {
+				return true;
+			}
+		}
+		return false;
+	}
+
+	/**
+	 * Validate element for its CDATA.
+	 *
+	 * @since 0.7
+	 *
+	 * @param DOMElement $element    Element.
+	 * @param array      $cdata_spec CDATA.
+	 * @return true|WP_Error True when valid or error when invalid.
+	 */
+	private function validate_cdata_for_node( $element, $cdata_spec ) {
+		if ( isset( $cdata_spec['blacklisted_cdata_regex'] ) ) {
+			if ( preg_match( '@' . $cdata_spec['blacklisted_cdata_regex']['regex'] . '@u', $element->textContent ) ) {
+				return new WP_Error( $cdata_spec['blacklisted_cdata_regex']['error_message'] );
+			}
+		} elseif ( isset( $cdata_spec['cdata_regex'] ) ) {
+			$delimiter = false === strpos( $cdata_spec['cdata_regex'], '@' ) ? '@' : '#';
+			if ( ! preg_match( $delimiter . $cdata_spec['cdata_regex'] . $delimiter . 'u', $element->textContent ) ) {
+				return new WP_Error( 'cdata_regex' );
+			}
+		}
+		return true;
+	}
+
+	/**
+	 * Determines is a node is currently valid per its tag specification.
+	 *
+	 * Checks to see if a node's placement with the DOM is be valid for the
+	 * given tag_spec. If there are restrictions placed on the type of node
+	 * that can be an immediate parent or an ancestor of this node, then make
+	 * sure those restrictions are met.
+	 *
+	 * @since 0.5
+	 *
+	 * @param DOMNode $node The node to validate.
+	 * @param array   $tag_spec The specification.
+	 * @return boolean $valid Whether the node's placement is valid.
+	 */
+	private function validate_tag_spec_for_node( $node, $tag_spec ) {
+
+		if ( ! empty( $tag_spec[ AMP_Rule_Spec::MANDATORY_PARENT ] ) && ! $this->has_parent( $node, $tag_spec[ AMP_Rule_Spec::MANDATORY_PARENT ] ) ) {
+			return false;
+		}
+
+		// Extension scripts must be in the head.
+		if ( isset( $tag_spec['extension_spec'] ) && ! $this->has_parent( $node, 'head' ) ) {
+			return false;
+		}
+
+		if ( ! empty( $tag_spec[ AMP_Rule_Spec::DISALLOWED_ANCESTOR ] ) ) {
+			foreach ( $tag_spec[ AMP_Rule_Spec::DISALLOWED_ANCESTOR ] as $disallowed_ancestor_node_name ) {
+				if ( $this->has_ancestor( $node, $disallowed_ancestor_node_name ) ) {
+					return false;
+				}
+			}
+		}
+
+		if ( ! empty( $tag_spec[ AMP_Rule_Spec::MANDATORY_ANCESTOR ] ) && ! $this->has_ancestor( $node, $tag_spec[ AMP_Rule_Spec::MANDATORY_ANCESTOR ] ) ) {
+			return false;
+		}
+
+		return true;
+	}
+
+	/**
+	 * Checks to see if a spec is potentially valid.
+	 *
+	 * Checks the given node based on the attributes present in the node.
+	 *
+	 * @note This can be a very expensive function. Use it sparingly.
+	 *
+	 * @param DOMNode $node           Node.
+	 * @param array[] $attr_spec_list Attribute Spec list.
+	 *
+	 * @return float Number of times the attribute spec list matched. If there was a mismatch, then 0 is returned. 0.5 is returned if there is an implicit match.
+	 */
+	private function validate_attr_spec_list_for_node( $node, $attr_spec_list ) {
+		/*
+		 * If node has no attributes there is no point in continuing, but if none of attributes
+		 * in the spec list are mandatory, then we give this a score.
+		 */
+		if ( ! $node->hasAttributes() ) {
+			foreach ( $attr_spec_list as $attr_name => $attr_spec_rule ) {
+				if ( isset( $attr_spec_rule[ AMP_Rule_Spec::MANDATORY ] ) ) {
+					return 0;
+				}
+			}
+			return 0.5;
+		}
+
+		if ( ! $node instanceof DOMElement ) {
+			/*
+			 * A DOMNode is not valid for checks so might
+			 * as well bail here is not an DOMElement.
+			 */
+			return 0;
+		}
+
+		foreach ( $node->attributes as $attr_name => $attr_node ) {
+			if ( ! isset( $attr_spec_list[ $attr_name ][ AMP_Rule_Spec::ALTERNATIVE_NAMES ] ) ) {
+				continue;
+			}
+			foreach ( $attr_spec_list[ $attr_name ][ AMP_Rule_Spec::ALTERNATIVE_NAMES ] as $attr_alt_name ) {
+				$attr_spec_list[ $attr_alt_name ] = $attr_spec_list[ $attr_name ];
+			}
+		}
+
+		$score = 0;
+
+		/*
+		 * Keep track of how many of the attribute spec rules are mandatory,
+		 * because if none are mandatory, then we will let this rule have a
+		 * score since all the invalid attributes can just be removed.
+		 */
+		$mandatory_count = 0;
+
+		/*
+		 * Iterate through each attribute rule in this attr spec list and run
+		 * the series of tests. Each filter is given a `$node`, an `$attr_name`,
+		 * and an `$attr_spec_rule`. If the `$attr_spec_rule` seems to be valid
+		 * for the given node, then the filter should increment the score by one.
+		 */
+		foreach ( $attr_spec_list as $attr_name => $attr_spec_rule ) {
+
+			// If attr spec rule is empty, then it allows anything.
+			if ( empty( $attr_spec_rule ) && $node->hasAttribute( $attr_name ) ) {
+				$score++;
+				continue;
+			}
+
+			// If a mandatory attribute is required, and attribute exists, pass.
+			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::MANDATORY ] ) ) {
+				$mandatory_count++;
+				$result = $this->check_attr_spec_rule_mandatory( $node, $attr_name, $attr_spec_rule );
+				if ( AMP_Rule_Spec::PASS === $result ) {
+					$score++;
+				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
+					return 0;
+				}
+			}
+
+			/*
+			 * Check 'value' - case sensitive
+			 * Given attribute's value must exactly equal value of the rule to pass.
+			 */
+			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE ] ) ) {
+				$result = $this->check_attr_spec_rule_value( $node, $attr_name, $attr_spec_rule );
+				if ( AMP_Rule_Spec::PASS === $result ) {
+					$score++;
+				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
+					return 0;
+				}
+			}
+
+			/*
+			 * Check 'value_regex' - case sensitive regex match
+			 * Given attribute's value must be a case insensitive match to regex pattern
+			 * specified by the value of rule to pass.
+			 */
+			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_REGEX ] ) ) {
+				$result = $this->check_attr_spec_rule_value_regex( $node, $attr_name, $attr_spec_rule );
+				if ( AMP_Rule_Spec::PASS === $result ) {
+					$score++;
+				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
+					return 0;
+				}
+			}
+
+			/*
+			 * Check 'value_casei' - case insensitive
+			 * Given attribute's value must be a case insensitive match to the value of
+			 * the rule to pass.
+			 */
+			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_CASEI ] ) ) {
+				$result = $this->check_attr_spec_rule_value_casei( $node, $attr_name, $attr_spec_rule );
+				if ( AMP_Rule_Spec::PASS === $result ) {
+					$score++;
+				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
+					return 0;
+				}
+			}
+
+			/*
+			 * Check 'value_regex_casei' - case insensitive regex match
+			 * Given attribute's value must be a case insensitive match to the regex
+			 * pattern specified by the value of the rule to pass.
+			 */
+			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_REGEX_CASEI ] ) ) {
+				$result = $this->check_attr_spec_rule_value_regex_casei( $node, $attr_name, $attr_spec_rule );
+				if ( AMP_Rule_Spec::PASS === $result ) {
+					$score++;
+				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
+					return 0;
+				}
+			}
+
+			/*
+			 * If given attribute's value is a URL with a protocol, the protocol must
+			 * be in the array specified by the rule's value to pass.
+			 */
+			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOWED_PROTOCOL ] ) ) {
+				$result = $this->check_attr_spec_rule_allowed_protocol( $node, $attr_name, $attr_spec_rule );
+				if ( AMP_Rule_Spec::PASS === $result ) {
+					$score++;
+				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
+					return 0;
+				}
+			}
+
+			/*
+			 * If given attribute's value is a URL with a host, the host must
+			 * be valid
+			 */
+			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ] ) ) {
+				$result = $this->check_attr_spec_rule_valid_url( $node, $attr_name, $attr_spec_rule );
+				if ( AMP_Rule_Spec::PASS === $result ) {
+					$score++;
+				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
+					return 0;
+				}
+			}
+
+			/*
+			 * If the given attribute's value is *not* a relative path, and the rule's
+			 * value is `false`, then pass.
+			 */
+			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOW_RELATIVE ] ) ) {
+				$result = $this->check_attr_spec_rule_disallowed_relative( $node, $attr_name, $attr_spec_rule );
+				if ( AMP_Rule_Spec::PASS === $result ) {
+					$score++;
+				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
+					return 0;
+				}
+			}
+
+			/*
+			 * If the given attribute's value exists, is non-empty and the rule's value
+			 * is false, then pass.
+			 */
+			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOW_EMPTY ] ) ) {
+				$result = $this->check_attr_spec_rule_disallowed_empty( $node, $attr_name, $attr_spec_rule );
+				if ( AMP_Rule_Spec::PASS === $result ) {
+					$score++;
+				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
+					return 0;
+				}
+			}
+
+			/*
+			 * If the given attribute's value is a URL and does not match any of the list
+			 * of domains in the value of the rule, then pass.
+			 */
+			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::DISALLOWED_DOMAIN ] ) ) {
+				$result = $this->check_attr_spec_rule_disallowed_domain( $node, $attr_name, $attr_spec_rule );
+				if ( AMP_Rule_Spec::PASS === $result ) {
+					$score++;
+				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
+					return 0;
+				}
+			}
+
+			/*
+			 * If the attribute's value exists and does not match the regex specified
+			 * by the rule's value, then pass.
+			 */
+			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::BLACKLISTED_VALUE_REGEX ] ) ) {
+				$result = $this->check_attr_spec_rule_blacklisted_value_regex( $node, $attr_name, $attr_spec_rule );
+				if ( AMP_Rule_Spec::PASS === $result ) {
+					$score++;
+				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
+					return 0;
+				}
+			}
+
+			// If the attribute's value exists and it matches the value properties spec.
+			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_PROPERTIES ] ) && $node->hasAttribute( $attr_name ) ) {
+				$result = $this->check_attr_spec_rule_value_properties( $node, $attr_name, $attr_spec_rule );
+				if ( AMP_Rule_Spec::PASS === $result ) {
+					$score++;
+				} elseif ( AMP_Rule_Spec::FAIL === $result ) {
+					return 0;
+				}
+			}
+		}
+
+		// Give the spec a score if it doesn't have any mandatory attributes.
+		if ( 0 === $mandatory_count && 0 === $score ) {
+			$score = 0.5;
+		}
+
+		return $score;
+	}
+
+	/**
+	 * Remove attributes from $node that are not listed in $allowed_attrs.
+	 *
+	 * @param DOMNode $node           Node.
+	 * @param array[] $attr_spec_list Attribute spec list.
+	 * @return DOMAttr[] Attributes to remove.
+	 */
+	private function get_disallowed_attributes_in_node( $node, $attr_spec_list ) {
+
+		if ( ! $node instanceof DOMElement ) {
+			/**
+			 * If $node is only a DOMNode and not a DOMElement we can't
+			 * remove an attribute from it anyway.  So bail out now.
+			 */
+			return array();
+		}
+
+		/*
+		 * We can't remove attributes inside the 'foreach' loop without
+		 * breaking the iteration. So we keep track of the attributes to
+		 * remove in the first loop, then remove them in the second loop.
+		 */
+		$attrs_to_remove = array();
+		foreach ( $node->attributes as $attr_name => $attr_node ) {
+			if ( ! $this->is_amp_allowed_attribute( $attr_node, $attr_spec_list ) ) {
+				$attrs_to_remove[] = $attr_node;
+			}
+		}
+
+		return $attrs_to_remove;
+	}
+
+	/**
+	 * Remove invalid AMP attributes values from $node that have been implicitly disallowed.
+	 *
+	 * Allowed values are found $this->globally_allowed_attributes and in parameter $attr_spec_list
+	 *
+	 * @param DOMNode   $node                       Node.
+	 * @param array[][] $attr_spec_list             Attribute spec list.
+	 * @param DOMAttr[] $attributes_pending_removal Attributes pending removal.
+	 * @return DOMAttr[]|false Attributes to remove, or false if the element itself should be removed.
+	 */
+	private function sanitize_disallowed_attribute_values_in_node( $node, $attr_spec_list, $attributes_pending_removal ) {
+
+		if ( ! $node instanceof DOMElement ) {
+			/*
+			 * If $node is only a DOMNode and not a DOMElement we can't
+			 * remove an attribute from it anyway.  So bail out now.
+			 */
+			return $attributes_pending_removal;
+		}
+
+		return $this->delegated_sanitize_disallowed_attribute_values_in_node(
+			$node,
+			array_merge(
+				$this->globally_allowed_attributes,
+				$attr_spec_list
+			),
+			$attributes_pending_removal
+		);
+	}
+
+	/**
+	 * Remove attributes values from $node that have been disallowed by AMP.
+	 *
+	 * @see $this->sanitize_disallowed_attribute_values_in_node() which delegates to this method
+	 *
+	 * @param DOMElement $node                       Node.
+	 * @param array[][]  $attr_spec_list             Attribute spec list.
+	 * @param DOMAttr[]  $attributes_pending_removal Attributes pending removal.
+	 * @return DOMAttr[]|false Attributes to remove, or false if the element itself should be removed.
+	 */
+	private function delegated_sanitize_disallowed_attribute_values_in_node( $node, $attr_spec_list, $attributes_pending_removal ) {
+		$attrs_to_remove = array();
+
+		foreach ( $attr_spec_list as $attr_name => $attr_val ) {
+			if ( isset( $attr_spec_list[ $attr_name ][ AMP_Rule_Spec::ALTERNATIVE_NAMES ] ) ) {
+				foreach ( $attr_spec_list[ $attr_name ][ AMP_Rule_Spec::ALTERNATIVE_NAMES ] as $attr_alt_name ) {
+					$attr_spec_list[ $attr_alt_name ] = $attr_spec_list[ $attr_name ];
+				}
+			}
+		}
+
+		foreach ( $node->attributes as $attr_name => $attr_node ) {
+
+			if ( ! isset( $attr_spec_list[ $attr_name ] ) || in_array( $attr_node, $attributes_pending_removal, true ) ) {
+				continue;
+			}
+
+			$should_remove_node = false;
+			$attr_spec_rule     = $attr_spec_list[ $attr_name ];
+
+			if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE ] ) &&
+				AMP_Rule_Spec::FAIL === $this->check_attr_spec_rule_value( $node, $attr_name, $attr_spec_rule ) ) {
+				$should_remove_node = true;
+			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_CASEI ] ) &&
+				AMP_Rule_Spec::FAIL === $this->check_attr_spec_rule_value_casei( $node, $attr_name, $attr_spec_rule ) ) {
+				$should_remove_node = true;
+			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_REGEX ] ) &&
+				AMP_Rule_Spec::FAIL === $this->check_attr_spec_rule_value_regex( $node, $attr_name, $attr_spec_rule ) ) {
+				$should_remove_node = true;
+			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_REGEX_CASEI ] ) &&
+				AMP_Rule_Spec::FAIL === $this->check_attr_spec_rule_value_regex_casei( $node, $attr_name, $attr_spec_rule ) ) {
+				$should_remove_node = true;
+			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOWED_PROTOCOL ] ) &&
+				AMP_Rule_Spec::FAIL === $this->check_attr_spec_rule_allowed_protocol( $node, $attr_name, $attr_spec_rule ) ) {
+				$should_remove_node = true;
+			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ] ) &&
+				AMP_Rule_Spec::FAIL === $this->check_attr_spec_rule_valid_url( $node, $attr_name, $attr_spec_rule ) ) {
+				$should_remove_node = true;
+			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOW_RELATIVE ] ) &&
+				AMP_Rule_Spec::FAIL === $this->check_attr_spec_rule_disallowed_relative( $node, $attr_name, $attr_spec_rule ) ) {
+				$should_remove_node = true;
+			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOW_EMPTY ] ) &&
+				AMP_Rule_Spec::FAIL === $this->check_attr_spec_rule_disallowed_empty( $node, $attr_name, $attr_spec_rule ) ) {
+				$should_remove_node = true;
+			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::DISALLOWED_DOMAIN ] ) &&
+				AMP_Rule_Spec::FAIL === $this->check_attr_spec_rule_disallowed_domain( $node, $attr_name, $attr_spec_rule ) ) {
+				$should_remove_node = true;
+			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::BLACKLISTED_VALUE_REGEX ] ) &&
+				AMP_Rule_Spec::FAIL === $this->check_attr_spec_rule_blacklisted_value_regex( $node, $attr_name, $attr_spec_rule ) ) {
+				$should_remove_node = true;
+			}
+
+			if ( $should_remove_node ) {
+				$is_mandatory =
+					isset( $attr_spec_rule[ AMP_Rule_Spec::MANDATORY ] )
+						? (bool) $attr_spec_rule[ AMP_Rule_Spec::MANDATORY ]
+						: false;
+
+				if ( $is_mandatory ) {
+					$this->remove_node( $node );
+					return false;
+				}
+
+				$attrs_to_remove[] = $attr_node;
+			}
+		}
+
+		// Remove the disallowed values.
+		foreach ( $attrs_to_remove as $attr_node ) {
+			if ( isset( $attr_spec_list[ $attr_node->nodeName ][ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOW_EMPTY ] ) &&
+				( true === $attr_spec_list[ $attr_node->nodeName ][ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOW_EMPTY ] ) ) {
+				$attr_node->nodeValue = '';
+			} else {
+				$attributes_pending_removal[] = $attr_node;
+			}
+		}
+
+		return $attributes_pending_removal;
+	}
+
+	/**
+	 * Check if attribute is mandatory determine whether it exists in $node.
+	 *
+	 * When checking for the given attribute it also checks valid alternates.
+	 *
+	 * @param DOMElement $node           Node.
+	 * @param string     $attr_name      Attribute name.
+	 * @param array[]    $attr_spec_rule Attribute spec rule.
+	 *
+	 * @return string:
+	 *      - AMP_Rule_Spec::PASS - $attr_name is mandatory and it exists
+	 *      - AMP_Rule_Spec::FAIL - $attr_name is mandatory, but doesn't exist
+	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name is not mandatory
+	 */
+	private function check_attr_spec_rule_mandatory( $node, $attr_name, $attr_spec_rule ) {
+		if ( isset( $attr_spec_rule[ AMP_Rule_Spec::MANDATORY ] ) && ( $attr_spec_rule[ AMP_Rule_Spec::MANDATORY ] ) ) {
+			if ( $node->hasAttribute( $attr_name ) ) {
+				return AMP_Rule_Spec::PASS;
+			} else {
+				// Check if an alternative name list is specified.
+				if ( isset( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] ) ) {
+					foreach ( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] as $alt_name ) {
+						if ( $node->hasAttribute( $alt_name ) ) {
+							return AMP_Rule_Spec::PASS;
+						}
+					}
+				}
+				return AMP_Rule_Spec::FAIL;
+			}
+		}
+		return AMP_Rule_Spec::NOT_APPLICABLE;
+	}
+
+	/**
+	 * Check if attribute has a value rule determine if its value is valid.
+	 *
+	 * Checks for value validity by matches against valid values.
+	 *
+	 * @param DOMElement $node           Node.
+	 * @param string     $attr_name      Attribute name.
+	 * @param array      $attr_spec_rule Attribute spec rule.
+	 *
+	 * @return string:
+	 *      - AMP_Rule_Spec::PASS - $attr_name has a value that matches the rule.
+	 *      - AMP_Rule_Spec::FAIL - $attr_name has a value that does *not* match rule.
+	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name does not exist or there
+	 *                                        is no rule for this attribute.
+	 */
+	private function check_attr_spec_rule_value( $node, $attr_name, $attr_spec_rule ) {
+		if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE ] ) ) {
+			if ( $node->hasAttribute( $attr_name ) ) {
+				if ( $this->check_matching_attribute_value( $attr_name, $node->getAttribute( $attr_name ), $attr_spec_rule[ AMP_Rule_Spec::VALUE ] ) ) {
+					return AMP_Rule_Spec::PASS;
+				} else {
+					return AMP_Rule_Spec::FAIL;
+				}
+			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] ) ) {
+				foreach ( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] as $alternative_name ) {
+					if ( $node->hasAttribute( $alternative_name ) ) {
+						if ( $this->check_matching_attribute_value( $attr_name, $node->getAttribute( $alternative_name ), $attr_spec_rule[ AMP_Rule_Spec::VALUE ] ) ) {
+							return AMP_Rule_Spec::PASS;
+						} else {
+							return AMP_Rule_Spec::FAIL;
+						}
+					}
+				}
+			}
+		}
+		return AMP_Rule_Spec::NOT_APPLICABLE;
+	}
+
+	/**
+	 * Check that an attribute's value matches is given spec value.
+	 *
+	 * This takes into account boolean attributes where value can match name (e.g. selected="selected").
+	 *
+	 * @since 0.7.0
+	 * @since 1.0.0 The spec value is now an array.
+	 *
+	 * @param string       $attr_name   Attribute name.
+	 * @param string       $attr_value  Attribute value.
+	 * @param string|array $spec_values Attribute spec value(s).
+	 * @return bool Is value valid.
+	 */
+	private function check_matching_attribute_value( $attr_name, $attr_value, $spec_values ) {
+		if ( is_string( $spec_values ) ) {
+			$spec_values = (array) $spec_values;
+		}
+		foreach ( $spec_values as $spec_value ) {
+			if ( $spec_value === $attr_value ) {
+				return true;
+			}
+
+			// Check for boolean attribute.
+			$is_bool_match = (
+				'' === $spec_value
+				&&
+				in_array( $attr_name, AMP_Rule_Spec::$boolean_attributes, true )
+				&&
+				strtolower( $attr_value ) === strtolower( $attr_name )
+			);
+			if ( $is_bool_match ) {
+				return true;
+			}
+		}
+		return false;
+	}
+
+	/**
+	 * Check if attribute has a value rule determine if its value matches ignoring case.
+	 *
+	 * @param DOMElement   $node           Node.
+	 * @param string       $attr_name      Attribute name.
+	 * @param array|string $attr_spec_rule Attribute spec rule.
+	 *
+	 * @return string:
+	 *      - AMP_Rule_Spec::PASS - $attr_name has a value that matches the rule.
+	 *      - AMP_Rule_Spec::FAIL - $attr_name has a value that does *not* match rule.
+	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name does not exist or there
+	 *                                        is no rule for this attribute.
+	 */
+	private function check_attr_spec_rule_value_casei( $node, $attr_name, $attr_spec_rule ) {
+		if ( ! isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_CASEI ] ) ) {
+			return AMP_Rule_Spec::NOT_APPLICABLE;
+		}
+
+		$result      = AMP_Rule_Spec::NOT_APPLICABLE;
+		$rule_values = (array) $attr_spec_rule[ AMP_Rule_Spec::VALUE_CASEI ];
+		foreach ( $rule_values as $rule_value ) {
+			$rule_value = strtolower( $rule_value );
+			if ( $node->hasAttribute( $attr_name ) ) {
+				$attr_value = strtolower( $node->getAttribute( $attr_name ) );
+				if ( $attr_value === (string) $rule_value ) {
+					return AMP_Rule_Spec::PASS;
+				} else {
+					$result = AMP_Rule_Spec::FAIL;
+				}
+			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] ) ) {
+				foreach ( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] as $alternative_name ) {
+					if ( $node->hasAttribute( $alternative_name ) ) {
+						$attr_value = strtolower( $node->getAttribute( $alternative_name ) );
+						if ( $attr_value === (string) $rule_value ) {
+							return AMP_Rule_Spec::PASS;
+						} else {
+							$result = AMP_Rule_Spec::FAIL;
+						}
+					}
+				}
+			}
+		}
+		return $result;
+	}
+
+	/**
+	 * Check if attribute has a regex value rule determine if it matches.
+	 *
+	 * @param DOMElement       $node           Node.
+	 * @param string           $attr_name      Attribute name.
+	 * @param array[]|string[] $attr_spec_rule Attribute spec rule.
+	 *
+	 * @return string:
+	 *      - AMP_Rule_Spec::PASS - $attr_name has a value that matches the rule.
+	 *      - AMP_Rule_Spec::FAIL - $attr_name has a value that does *not* match rule.
+	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name does not exist or there
+	 *                                        is no rule for this attribute.
+	 */
+	private function check_attr_spec_rule_value_regex( $node, $attr_name, $attr_spec_rule ) {
+		// Check 'value_regex' - case sensitive regex match.
+		if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_REGEX ] ) && $node->hasAttribute( $attr_name ) ) {
+			$rule_value = $attr_spec_rule[ AMP_Rule_Spec::VALUE_REGEX ];
+			$rule_value = str_replace( '/', '\\/', $rule_value );
+
+			/*
+			 * The regex pattern has '^' and '$' though they are not in the AMP spec.
+			 * Leaving them out would allow both '_blank' and 'yyy_blankzzz' to be
+			 * matched by a regex rule of '(_blank|_self|_top)'. As the AMP JS validator
+			 * only accepts '_blank' we leave it this way for now.
+			 */
+			if ( preg_match( '/^(' . $rule_value . ')$/u', $node->getAttribute( $attr_name ) ) ) {
+				return AMP_Rule_Spec::PASS;
+			} else {
+				return AMP_Rule_Spec::FAIL;
+			}
+		}
+		return AMP_Rule_Spec::NOT_APPLICABLE;
+	}
+
+	/**
+	 * Check if attribute has a case-insensitive regex value rule determine if it matches.
+	 *
+	 * @param DOMElement       $node           Node.
+	 * @param string           $attr_name      Attribute name.
+	 * @param array[]|string[] $attr_spec_rule Attribute spec rule.
+	 *
+	 * @return string:
+	 *      - AMP_Rule_Spec::PASS - $attr_name has a value that matches the rule.
+	 *      - AMP_Rule_Spec::FAIL - $attr_name has a value that does *not* match rule.
+	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name does not exist or there
+	 *                                        is no rule for this attribute.
+	 */
+	private function check_attr_spec_rule_value_regex_casei( $node, $attr_name, $attr_spec_rule ) {
+		/**
+		 * Check 'value_regex_casei' - case insensitive regex match
+		 */
+		if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_REGEX_CASEI ] ) && $node->hasAttribute( $attr_name ) ) {
+			$rule_value = $attr_spec_rule[ AMP_Rule_Spec::VALUE_REGEX_CASEI ];
+			$rule_value = str_replace( '/', '\\/', $rule_value );
+
+			// See note above regarding the '^' and '$' that are added here.
+			if ( preg_match( '/^(' . $rule_value . ')$/ui', $node->getAttribute( $attr_name ) ) ) {
+				return AMP_Rule_Spec::PASS;
+			} else {
+				return AMP_Rule_Spec::FAIL;
+			}
+		}
+		return AMP_Rule_Spec::NOT_APPLICABLE;
+	}
+
+	/**
+	 * Check if attribute has a valid host value
+	 *
+	 * @since 0.7
+	 *
+	 * @param DOMElement       $node           Node.
+	 * @param string           $attr_name      Attribute name.
+	 * @param array[]|string[] $attr_spec_rule Attribute spec rule.
+	 *
+	 * @return string:
+	 *      - AMP_Rule_Spec::PASS - $attr_name has a value that matches the rule.
+	 *      - AMP_Rule_Spec::FAIL - $attr_name has a value that does *not* match rule.
+	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name does not exist or there
+	 *                                        is no rule for this attribute.
+	 */
+	private function check_attr_spec_rule_valid_url( $node, $attr_name, $attr_spec_rule ) {
+		if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ] ) ) {
+			if ( $node->hasAttribute( $attr_name ) ) {
+				foreach ( $this->extract_attribute_urls( $node->getAttributeNode( $attr_name ) ) as $url ) {
+					$url = urldecode( $url );
+
+					// Check if the protocol contains invalid chars (protocolCharIsValid: https://github.com/ampproject/amphtml/blob/af1e3a550feeafd732226202b8d1f26dcefefa18/validator/engine/parse-url.js#L31-L39).
+					$protocol = $this->parse_protocol( $url );
+					if ( isset( $protocol ) ) {
+						if ( ! preg_match( '/^[a-zA-Z0-9\+-]+/i', $protocol ) ) {
+							return AMP_Rule_Spec::FAIL;
+						}
+						$url = substr( $url, strlen( $protocol ) + 1 );
+					}
+
+					// Check if the host contains invalid chars (hostCharIsValid: https://github.com/ampproject/amphtml/blob/af1e3a550feeafd732226202b8d1f26dcefefa18/validator/engine/parse-url.js#L62-L103).
+					$host = wp_parse_url( $url, PHP_URL_HOST );
+					if ( $host && preg_match( '/[!"#$%&\'()*+,\/:;<=>?@[\]^`{|}~\s]/i', $host ) ) {
+						return AMP_Rule_Spec::FAIL;
+					}
+				}
+
+				return AMP_Rule_Spec::PASS;
+			}
+		}
+
+		return AMP_Rule_Spec::NOT_APPLICABLE;
+	}
+
+	/**
+	 * Parse protocol from URL.
+	 *
+	 * This may not be a valid protocol (scheme), but it will be where the protocol should be in the URL.
+	 *
+	 * @link https://github.com/ampproject/amphtml/blob/af1e3a550feeafd732226202b8d1f26dcefefa18/validator/engine/parse-url.js#L235-L282
+	 * @param string $url URL.
+	 * @return string|null Protocol without colon if matched. Otherwise null.
+	 */
+	private function parse_protocol( $url ) {
+		if ( preg_match( '#^[^/]+(?=:)#', $url, $matches ) ) {
+			return $matches[0];
+		}
+		return null;
+	}
+
+	/**
+	 * Check if attribute has a protocol value rule determine if it matches.
+	 *
+	 * @param DOMElement       $node           Node.
+	 * @param string           $attr_name      Attribute name.
+	 * @param array[]|string[] $attr_spec_rule Attribute spec rule.
+	 *
+	 * @return string:
+	 *      - AMP_Rule_Spec::PASS - $attr_name has a value that matches the rule.
+	 *      - AMP_Rule_Spec::FAIL - $attr_name has a value that does *not* match rule.
+	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name does not exist or there
+	 *                                        is no rule for this attribute.
+	 */
+	private function check_attr_spec_rule_allowed_protocol( $node, $attr_name, $attr_spec_rule ) {
+		if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOWED_PROTOCOL ] ) ) {
+			if ( $node->hasAttribute( $attr_name ) ) {
+				foreach ( $this->extract_attribute_urls( $node->getAttributeNode( $attr_name ) ) as $url ) {
+					$url_scheme = $this->parse_protocol( $url );
+					if ( isset( $url_scheme ) && ! in_array( strtolower( $url_scheme ), $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOWED_PROTOCOL ], true ) ) {
+						return AMP_Rule_Spec::FAIL;
+					}
+				}
+				return AMP_Rule_Spec::PASS;
+			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] ) ) {
+				foreach ( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] as $alternative_name ) {
+					if ( $node->hasAttribute( $alternative_name ) ) {
+						foreach ( $this->extract_attribute_urls( $node->getAttributeNode( $alternative_name ), $attr_name ) as $url ) {
+							$url_scheme = $this->parse_protocol( $url );
+							if ( isset( $url_scheme ) && ! in_array( strtolower( $url_scheme ), $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOWED_PROTOCOL ], true ) ) {
+								return AMP_Rule_Spec::FAIL;
+							}
+						}
+						return AMP_Rule_Spec::PASS;
+					}
+				}
+			}
+		}
+		return AMP_Rule_Spec::NOT_APPLICABLE;
+	}
+
+	/**
+	 * Extract URLs from attribute.
+	 *
+	 * @param DOMAttr     $attribute_node Attribute node.
+	 * @param string|null $spec_attr_name Non-alternative attribute name for the spec.
+	 * @return string[] List of URLs.
+	 */
+	private function extract_attribute_urls( $attribute_node, $spec_attr_name = null ) {
+		/*
+		 * Handle the srcset special case where the attribute value can contain multiple parts, each in the format `URL [WIDTH] [PIXEL_DENSITY]`.
+		 * So we split the srcset attribute value by commas and then return the first token of each item, omitting width descriptor and pixel density descriptor.
+		 * This splitting cannot be done for other URLs because it a comma can appear in a URL itself generally, but the syntax can break in srcset,
+		 * unless the commas are URL-encoded.
+		 */
+		if ( 'srcset' === $attribute_node->nodeName || 'srcset' === $spec_attr_name ) {
+			return array_filter( array_map(
+				function ( $srcset_part ) {
+					// Remove descriptors for width and pixel density.
+					return preg_replace( '/\s.*$/', '', trim( $srcset_part ) );
+				},
+				preg_split( '/\s*,\s*/', $attribute_node->nodeValue )
+			) );
+		} else {
+			return array( $attribute_node->nodeValue );
+		}
+	}
+
+	/**
+	 * Check if attribute has disallowed relative URL value according to rule spec.
+	 *
+	 * @param DOMElement       $node           Node.
+	 * @param string           $attr_name      Attribute name.
+	 * @param array[]|string[] $attr_spec_rule Attribute spec rule.
+	 *
+	 * @return string:
+	 *      - AMP_Rule_Spec::PASS - $attr_name has a value that matches the rule.
+	 *      - AMP_Rule_Spec::FAIL - $attr_name has a value that does *not* match rule.
+	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name does not exist or there
+	 *                                        is no rule for this attribute.
+	 */
+	private function check_attr_spec_rule_disallowed_relative( $node, $attr_name, $attr_spec_rule ) {
+		if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOW_RELATIVE ] ) && ! ( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOW_RELATIVE ] ) ) {
+			if ( $node->hasAttribute( $attr_name ) ) {
+				foreach ( $this->extract_attribute_urls( $node->getAttributeNode( $attr_name ) ) as $url ) {
+					$parsed_url = wp_parse_url( $url );
+
+					/*
+					 *  The JS AMP validator seems to consider 'relative' to mean
+					 *  *protocol* relative, not *host* relative for this rule. So,
+					 *  a url with an empty 'scheme' is considered "relative" by AMP.
+					 *  ie. '//domain.com/path' and '/path' should both be considered
+					 *  relative for purposes of AMP validation.
+					 */
+					if ( empty( $parsed_url['scheme'] ) ) {
+						return AMP_Rule_Spec::FAIL;
+					}
+				}
+				return AMP_Rule_Spec::PASS;
+			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] ) ) {
+				foreach ( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] as $alternative_name ) {
+					if ( $node->hasAttribute( $alternative_name ) ) {
+						foreach ( $this->extract_attribute_urls( $node->getAttributeNode( $alternative_name ), $attr_name ) as $url ) {
+							$parsed_url = wp_parse_url( $url );
+							if ( empty( $parsed_url['scheme'] ) ) {
+								return AMP_Rule_Spec::FAIL;
+							}
+						}
+					}
+				}
+				return AMP_Rule_Spec::PASS;
+			}
+		}
+		return AMP_Rule_Spec::NOT_APPLICABLE;
+	}
+
+	/**
+	 * Check if attribute has disallowed empty value rule determine if value is empty.
+	 *
+	 * @param DOMElement       $node           Node.
+	 * @param string           $attr_name      Attribute name.
+	 * @param array[]|string[] $attr_spec_rule Attribute spec rule.
+	 *
+	 * @return string:
+	 *      - AMP_Rule_Spec::PASS - $attr_name has a value that matches the rule.
+	 *      - AMP_Rule_Spec::FAIL - $attr_name has a value that does *not* match rule.
+	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name does not exist or there
+	 *                                        is no rule for this attribute.
+	 */
+	private function check_attr_spec_rule_disallowed_empty( $node, $attr_name, $attr_spec_rule ) {
+		if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOW_EMPTY ] ) && ! ( $attr_spec_rule[ AMP_Rule_Spec::VALUE_URL ][ AMP_Rule_Spec::ALLOW_EMPTY ] ) && $node->hasAttribute( $attr_name ) ) {
+			$attr_value = $node->getAttribute( $attr_name );
+			if ( empty( $attr_value ) ) {
+				return AMP_Rule_Spec::FAIL;
+			}
+			return AMP_Rule_Spec::PASS;
+		}
+		return AMP_Rule_Spec::NOT_APPLICABLE;
+	}
+
+	/**
+	 * Check if attribute has disallowed domain value rule determine if value matches.
+	 *
+	 * @param DOMElement       $node           Node.
+	 * @param string           $attr_name      Attribute name.
+	 * @param array[]|string[] $attr_spec_rule Attribute spec rule.
+	 *
+	 * @return string:
+	 *      - AMP_Rule_Spec::PASS - $attr_name has a value that matches the rule.
+	 *      - AMP_Rule_Spec::FAIL - $attr_name has a value that does *not* match rule.
+	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name does not exist or there
+	 *                                        is no rule for this attribute.
+	 */
+	private function check_attr_spec_rule_disallowed_domain( $node, $attr_name, $attr_spec_rule ) {
+		if ( isset( $attr_spec_rule[ AMP_Rule_Spec::DISALLOWED_DOMAIN ] ) && $node->hasAttribute( $attr_name ) ) {
+			$attr_value = $node->getAttribute( $attr_name );
+			$url_domain = wp_parse_url( $attr_value, PHP_URL_HOST );
+			if ( ! empty( $url_domain ) ) {
+				foreach ( $attr_spec_rule[ AMP_Rule_Spec::DISALLOWED_DOMAIN ] as $disallowed_domain ) {
+					if ( strtolower( $url_domain ) === strtolower( $disallowed_domain ) ) {
+
+						// Found a disallowed domain, fail validation.
+						return AMP_Rule_Spec::FAIL;
+					}
+				}
+				return AMP_Rule_Spec::PASS;
+			}
+		}
+		return AMP_Rule_Spec::NOT_APPLICABLE;
+	}
+
+	/**
+	 * Check if attribute has blacklisted value via regex match determine if value matches.
+	 *
+	 * @since 0.5
+	 *
+	 * @param DOMElement       $node           Node.
+	 * @param string           $attr_name      Attribute name.
+	 * @param array[]|string[] $attr_spec_rule Attribute spec rule.
+	 *
+	 * @return string:
+	 *      - AMP_Rule_Spec::PASS - $attr_name has a value that matches the rule.
+	 *      - AMP_Rule_Spec::FAIL - $attr_name has a value that does *not* match rule.
+	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name does not exist or there
+	 *                                        is no rule for this attribute.
+	 */
+	private function check_attr_spec_rule_blacklisted_value_regex( $node, $attr_name, $attr_spec_rule ) {
+		if ( isset( $attr_spec_rule[ AMP_Rule_Spec::BLACKLISTED_VALUE_REGEX ] ) ) {
+			$pattern = '/' . $attr_spec_rule[ AMP_Rule_Spec::BLACKLISTED_VALUE_REGEX ] . '/u';
+			if ( $node->hasAttribute( $attr_name ) ) {
+				$attr_value = $node->getAttribute( $attr_name );
+				if ( preg_match( $pattern, $attr_value ) ) {
+					return AMP_Rule_Spec::FAIL;
+				} else {
+					return AMP_Rule_Spec::PASS;
+				}
+			} elseif ( isset( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] ) ) {
+				foreach ( $attr_spec_rule[ AMP_Rule_Spec::ALTERNATIVE_NAMES ] as $alternative_name ) {
+					if ( $node->hasAttribute( $alternative_name ) ) {
+						$attr_value = $node->getAttribute( $alternative_name );
+						if ( preg_match( $pattern, $attr_value ) ) {
+							return AMP_Rule_Spec::FAIL;
+						} else {
+							return AMP_Rule_Spec::PASS;
+						}
+					}
+				}
+			}
+		}
+		return AMP_Rule_Spec::NOT_APPLICABLE;
+	}
+
+	/**
+	 * Check if attribute has valid properties.
+	 *
+	 * @since 0.7
+	 *
+	 * @param DOMElement       $node           Node.
+	 * @param string           $attr_name      Attribute name.
+	 * @param array[]|string[] $attr_spec_rule Attribute spec rule.
+	 *
+	 * @return string:
+	 *      - AMP_Rule_Spec::PASS - $attr_name has a value that matches the rule.
+	 *      - AMP_Rule_Spec::FAIL - $attr_name has a value that does *not* match rule.
+	 *      - AMP_Rule_Spec::NOT_APPLICABLE - $attr_name does not exist or there
+	 *                                        is no rule for this attribute.
+	 */
+	private function check_attr_spec_rule_value_properties( $node, $attr_name, $attr_spec_rule ) {
+		if ( isset( $attr_spec_rule[ AMP_Rule_Spec::VALUE_PROPERTIES ] ) && $node->hasAttribute( $attr_name ) ) {
+			$properties = array();
+			foreach ( explode( ',', $node->getAttribute( $attr_name ) ) as $pair ) {
+				$pair_parts = explode( '=', $pair, 2 );
+				if ( 2 !== count( $pair_parts ) ) {
+					return 0;
+				}
+				$properties[ trim( strtolower( $pair_parts[0] ) ) ] = trim( $pair_parts[1] );
+			}
+
+			// Fail if there are unrecognized properties.
+			if ( count( array_diff( array_keys( $properties ), array_keys( $attr_spec_rule[ AMP_Rule_Spec::VALUE_PROPERTIES ] ) ) ) > 0 ) {
+				return AMP_Rule_Spec::FAIL;
+			}
+
+			foreach ( $attr_spec_rule[ AMP_Rule_Spec::VALUE_PROPERTIES ] as $prop_name => $property_spec ) {
+
+				// Mandatory property is missing.
+				if ( ! empty( $property_spec['mandatory'] ) && ! isset( $properties[ $prop_name ] ) ) {
+					return AMP_Rule_Spec::FAIL;
+				}
+
+				if ( ! isset( $properties[ $prop_name ] ) ) {
+					continue;
+				}
+
+				$prop_value = $properties[ $prop_name ];
+
+				// Required value is absent, so fail.
+				$required_value = null;
+				if ( isset( $property_spec['value'] ) ) {
+					$required_value = $property_spec['value'];
+				} elseif ( isset( $property_spec['value_double'] ) ) {
+					$required_value = $property_spec['value_double'];
+					$prop_value     = (double) $prop_value;
+				}
+				if ( isset( $required_value ) && $prop_value !== $required_value ) {
+					return AMP_Rule_Spec::FAIL;
+				}
+			}
+			return AMP_Rule_Spec::PASS;
+		}
+		return AMP_Rule_Spec::NOT_APPLICABLE;
+	}
+
+	/**
+	 * Determine if the supplied attribute name is allowed for AMP.
+	 *
+	 * @since 0.5
+	 *
+	 * @param DOMAttr          $attr_node      Attribute node.
+	 * @param array[]|string[] $attr_spec_list Attribute spec list.
+	 * @return bool Return true if attribute name is valid for this attr_spec_list, false otherwise.
+	 */
+	private function is_amp_allowed_attribute( $attr_node, $attr_spec_list ) {
+		$attr_name = $attr_node->nodeName;
+		if (
+			isset( $attr_spec_list[ $attr_name ] )
+			||
+			'data-' === substr( $attr_name, 0, 5 )
+			||
+			// Allow the 'amp' or '⚡' attribute in <html>, like <html ⚡>.
+			( 'html' === $attr_node->parentNode->nodeName && in_array( $attr_node->nodeName, array( 'amp', '⚡' ), true ) )
+		) {
+			return true;
+		}
+
+		$is_allowed_alt_name_attr = (
+			isset( $this->rev_alternate_attr_name_lookup[ $attr_name ] )
+			&&
+			isset( $attr_spec_list[ $this->rev_alternate_attr_name_lookup[ $attr_name ] ] )
+		);
+		if ( $is_allowed_alt_name_attr ) {
+			return true;
+		}
+
+		/*
+		 * Handle special case for amp-selector where its reference points do not have to be direct children.
+		 * This is noted as a special case in the AMP validator spec for amp-selector, so that is why it is
+		 * a special case here in this method. It is also implemented in this way for the sake of efficiency
+		 * to prevent having to waste time in process_node() merging attribute lists. For more on amp-selector's
+		 * unique reference point, see:
+		 * https://github.com/ampproject/amphtml/blob/1526498116488/extensions/amp-selector/validator-amp-selector.protoascii#L81-L91
+		 */
+		$reference_point_spec = AMP_Allowed_Tags_Generated::get_reference_point_spec( 'AMP-SELECTOR option' );
+		if ( isset( $reference_point_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ][ $attr_name ] ) ) {
+			$parent = $attr_node->parentNode;
+			while ( $parent ) {
+				if ( 'amp-selector' === $parent->nodeName ) {
+					return true;
+				}
+				$parent = $parent->parentNode;
+			}
+		}
+
+		return false;
+	}
+
+	/**
+	 * Determine if the supplied $node's HTML tag is allowed for AMP.
+	 *
+	 * @since 0.5
+	 *
+	 * @param DOMNode $node Node.
+	 * @return bool Return true if the specified node's name is an AMP allowed tag, false otherwise.
+	 */
+	private function is_amp_allowed_tag( $node ) {
+		if ( ! $node instanceof DOMElement ) {
+			return false;
+		}
+		/**
+		 * Return true if node is an allowed tags or is a text or comment node.
+		 */
+		return (
+			( XML_TEXT_NODE === $node->nodeType ) ||
+			isset( $this->allowed_tags[ $node->nodeName ] ) ||
+			( XML_COMMENT_NODE === $node->nodeType ) ||
+			( XML_CDATA_SECTION_NODE === $node->nodeType )
+		);
+	}
+
+	/**
+	 * Determine if the supplied $node has a parent with the specified spec name.
+	 *
+	 * @since 0.5
+	 *
+	 * @todo It would be more robust if the the actual tag spec were looked up and then matched against the parent, but this is currently overkill.
+	 *
+	 * @param DOMNode $node             Node.
+	 * @param string  $parent_spec_name Parent spec name, for example 'body' or 'form [method=post]'.
+	 * @return bool Return true if given node has direct parent with the given name, false otherwise.
+	 */
+	private function has_parent( $node, $parent_spec_name ) {
+		if ( ! $node ) {
+			return false;
+		}
+		$parsed_spec_name = $this->parse_tag_and_attributes_from_spec_name( $parent_spec_name );
+
+		if ( ! $node->parentNode || $node->parentNode->nodeName !== $parsed_spec_name['tag_name'] ) {
+			return false;
+		}
+
+		// Ensure attributes match; if not move up to the next node.
+		foreach ( $parsed_spec_name['attributes'] as $attr_name => $attr_value ) {
+			if ( $node instanceof DOMElement && strtolower( $node->getAttribute( $attr_name ) ) !== $attr_value ) {
+				return false;
+			}
+		}
+
+		return true;
+	}
+
+	/**
+	 * Determine if the supplied $node has an ancestor with the specified tag name.
+	 *
+	 * @since 0.5
+	 *
+	 * @param DOMNode $node              Node.
+	 * @param string  $ancestor_tag_name Ancestor tag name.
+	 * @return bool Return true if given node has any ancestor with the give name, false otherwise.
+	 */
+	private function has_ancestor( $node, $ancestor_tag_name ) {
+		if ( $this->get_ancestor_with_matching_spec_name( $node, $ancestor_tag_name ) ) {
+			return true;
+		}
+		return false;
+	}
+
+	/**
+	 * Parse tag name and attributes from spec name.
+	 *
+	 * Given a spec name like 'form [method=post]', extract the tag name 'form' and the attributes.
+	 *
+	 * @todo This is admittedly rudimentary. It would be more robust to actually look up the tag spec by the name and obtain the required attributes from there, but this is not necessary yet.
+	 *
+	 * @param string $spec_name Spec name.
+	 * @return array Tag name and attributes.
+	 */
+	private function parse_tag_and_attributes_from_spec_name( $spec_name ) {
+		static $parsed_specs = array();
+		if ( isset( $parsed_specs[ $spec_name ] ) ) {
+			return $parsed_specs[ $spec_name ];
+		}
+
+		$attributes = array();
+
+		/*
+		 * This matches spec names like:
+		 * - body
+		 * - form [method=post]
+		 * - form > div [submit-error][template]
+		 */
+		if ( preg_match( '/^(?P<ancestors>.+? )?(?P<tag_name>[a-z0-9_-]+?)( (?P<raw_attrs>\[.+?\]))?$/i', $spec_name, $matches ) ) {
+			$tag_name = $matches['tag_name'];
+
+			if ( isset( $matches['raw_attrs'] ) ) {
+				$raw_attr_pairs = explode( '][', trim( $matches['raw_attrs'], '[]' ) );
+				foreach ( $raw_attr_pairs as $raw_attr_pair ) {
+					$raw_attr_pair = explode( '=', $raw_attr_pair );
+
+					$attr_key = $raw_attr_pair[0];
+					$attr_val = isset( $raw_attr_pair[1] ) ? $raw_attr_pair[1] : true;
+
+					$attributes[ $attr_key ] = $attr_val;
+				}
+			}
+		} else {
+			$tag_name = strtok( $spec_name, ' ' ); // Fallback case.
+		}
+
+		$parsed_specs[ $spec_name ] = compact( 'tag_name', 'attributes' );
+		return $parsed_specs[ $spec_name ];
+	}
+
+	/**
+	 * Get the first ancestor node matching the specified tag name for the supplied $node.
+	 *
+	 * @since 0.5
+	 * @todo It would be more robust if the the actual tag spec were looked up and then matched for each ancestor, but this is currently overkill.
+	 *
+	 * @param DOMNode $node               Node.
+	 * @param string  $ancestor_spec_name Ancestor spec name, e.g. 'body' or 'form [method=post]'.
+	 * @return DOMNode|null Returns an ancestor node for the name specified, or null if not found.
+	 */
+	private function get_ancestor_with_matching_spec_name( $node, $ancestor_spec_name ) {
+		$parsed_spec_name = $this->parse_tag_and_attributes_from_spec_name( $ancestor_spec_name );
+
+		while ( $node && $node->parentNode ) {
+			$node = $node->parentNode;
+			if ( $node->nodeName === $parsed_spec_name['tag_name'] ) {
+
+				// Ensure attributes match; if not move up to the next node.
+				foreach ( $parsed_spec_name['attributes'] as $attr_name => $attr_value ) {
+					$match = (
+						$node instanceof DOMElement
+						&&
+						true === $attr_value ? $node->hasAttribute( $attr_name ) : strtolower( $node->getAttribute( $attr_name ) ) === $attr_value
+					);
+					if ( ! $match ) {
+						continue 2;
+					}
+				}
+
+				return $node;
+			}
+		}
+		return null;
+	}
+
+	/**
+	 * Replaces the given node with it's child nodes, if any
+	 *
+	 * Also adds them to the stack for processing by the sanitize() function.
+	 *
+	 * @since 0.3.3
+	 * @since 1.0 Fix silently removing unrecognized elements.
+	 * @see https://github.com/Automattic/amp-wp/issues/1100
+	 *
+	 * @param DOMNode $node Node.
+	 */
+	private function replace_node_with_children( $node ) {
+
+		// If node has no children or no parent, just remove the node.
+		if ( ! $node->hasChildNodes() || ! $node->parentNode ) {
+			$this->remove_node( $node );
+
+			return;
+		}
+
+		/*
+		 * If node has children, replace it with them and push children onto stack
+		 *
+		 * Create a DOM fragment to hold the children
+		 */
+		$fragment = $this->dom->createDocumentFragment();
+
+		// Add all children to fragment/stack.
+		$child = $node->firstChild;
+		while ( $child ) {
+			$fragment->appendChild( $child );
+			$this->stack[] = $child;
+			$child         = $node->firstChild;
+		}
+
+		// Prevent double-reporting nodes that are rejected for sanitization.
+		if ( isset( $this->should_not_replace_nodes[ $node->nodeName ] ) && in_array( $node, $this->should_not_replace_nodes[ $node->nodeName ], true ) ) {
+			return;
+		}
+
+		// Replace node with fragment.
+		$should_replace = $this->should_sanitize_validation_error( array(), compact( 'node' ) );
+		if ( $should_replace ) {
+			$node->parentNode->replaceChild( $fragment, $node );
+		} else {
+			$this->should_not_replace_nodes[ $node->nodeName ][] = $node;
+		}
+	}
+
+	/**
+	 * Removes a node from its parent node.
+	 *
+	 * If removing the node makes the parent node empty, then it will remove the parent
+	 * too. It will Continue until a non-empty parent or the 'body' element is reached.
+	 *
+	 * @since 0.5
+	 *
+	 * @param DOMNode $node Node.
+	 */
+	private function remove_node( $node ) {
+		/**
+		 * Parent.
+		 *
+		 * @var DOMNode $parent
+		 */
+		$parent = $node->parentNode;
+		if ( $node && $parent ) {
+			$this->remove_invalid_child( $node );
+		}
+		while ( $parent && ! $parent->hasChildNodes() && $this->root_element !== $parent ) {
+			$node   = $parent;
+			$parent = $parent->parentNode;
+			if ( $parent ) {
+				$parent->removeChild( $node );
+			}
+		}
+	}
+}
diff --git a/includes/sanitizers/class-amp-video-sanitizer.php b/includes/sanitizers/class-amp-video-sanitizer.php
new file mode 100644
index 00000000000..201975e631c
--- /dev/null
+++ b/includes/sanitizers/class-amp-video-sanitizer.php
@@ -0,0 +1,231 @@
+<?php
+/**
+ * Class AMP_Video_Sanitizer.
+ *
+ * @package AMP
+ */
+
+/**
+ * Class AMP_Video_Sanitizer
+ *
+ * @since 0.2
+ *
+ * Converts <video> tags to <amp-video>
+ */
+class AMP_Video_Sanitizer extends AMP_Base_Sanitizer {
+
+	/**
+	 * Value used for height attribute when $attributes['height'] is empty.
+	 *
+	 * @since 0.2
+	 *
+	 * @const int
+	 */
+	const FALLBACK_HEIGHT = 400;
+
+	/**
+	 * Tag.
+	 *
+	 * @var string HTML <video> tag to identify and replace with AMP version.
+	 *
+	 * @since 0.2
+	 */
+	public static $tag = 'video';
+
+	/**
+	 * Get mapping of HTML selectors to the AMP component selectors which they may be converted into.
+	 *
+	 * @return array Mapping.
+	 */
+	public function get_selector_conversion_mapping() {
+		return array(
+			'video' => array( 'amp-video', 'amp-youtube' ),
+		);
+	}
+
+	/**
+	 * Sanitize the <video> elements from the HTML contained in this instance's DOMDocument.
+	 *
+	 * @since 0.2
+	 * @since 1.0 Set the filtered child node's src attribute.
+	 */
+	public function sanitize() {
+		$nodes     = $this->dom->getElementsByTagName( self::$tag );
+		$num_nodes = $nodes->length;
+		if ( 0 === $num_nodes ) {
+			return;
+		}
+
+		for ( $i = $num_nodes - 1; $i >= 0; $i-- ) {
+			$node           = $nodes->item( $i );
+			$amp_data       = $this->get_data_amp_attributes( $node );
+			$old_attributes = AMP_DOM_Utils::get_node_attributes_as_assoc_array( $node );
+			$old_attributes = $this->filter_data_amp_attributes( $old_attributes, $amp_data );
+
+			$sources_count  = 0;
+			$new_attributes = $this->filter_attributes( $old_attributes );
+			$layout         = isset( $amp_data['layout'] ) ? $amp_data['layout'] : false;
+			if ( isset( $new_attributes['src'] ) ) {
+				$new_attributes = $this->filter_video_dimensions( $new_attributes, $new_attributes['src'] );
+				if ( $new_attributes['src'] ) {
+					$sources_count++;
+				}
+			}
+
+			// Gather all child nodes and supply empty video dimensions from sources.
+			$fallback    = null;
+			$child_nodes = array();
+			while ( $node->firstChild ) {
+				$child_node = $node->removeChild( $node->firstChild );
+				if ( $child_node instanceof DOMElement && 'source' === $child_node->nodeName && $child_node->hasAttribute( 'src' ) ) {
+					$src = $this->maybe_enforce_https_src( $child_node->getAttribute( 'src' ), true );
+					if ( ! $src ) {
+						// @todo $this->remove_invalid_child( $child_node ), but this will require refactoring the while loop since it uses firstChild.
+						continue; // Skip adding source.
+					}
+					$sources_count++;
+					$child_node->setAttribute( 'src', $src );
+					$new_attributes = $this->filter_video_dimensions( $new_attributes, $src );
+				}
+
+				if ( ! $fallback && $child_node instanceof DOMElement && ! ( 'source' === $child_node->nodeName || 'track' === $child_node->nodeName ) ) {
+					$fallback = $child_node;
+					$fallback->setAttribute( 'fallback', '' );
+				}
+
+				$child_nodes[] = $child_node;
+			}
+
+			$new_attributes = $this->filter_attachment_layout_attributes( $node, $new_attributes, $layout );
+			if ( empty( $new_attributes['layout'] ) && ! empty( $new_attributes['width'] ) && ! empty( $new_attributes['height'] ) ) {
+				$new_attributes['layout'] = 'responsive';
+			}
+			$new_attributes = $this->set_layout( $new_attributes );
+
+			// @todo Make sure poster and artwork attributes are HTTPS.
+			$new_node = AMP_DOM_Utils::create_node( $this->dom, 'amp-video', $new_attributes );
+			foreach ( $child_nodes as $child_node ) {
+				$new_node->appendChild( $child_node );
+			}
+
+			/*
+			 * If the node has at least one valid source, replace the old node with it.
+			 * Otherwise, just remove the node.
+			 *
+			 * TODO: Add a fallback handler.
+			 * See: https://github.com/ampproject/amphtml/issues/2261
+			 */
+			if ( 0 === $sources_count ) {
+				$this->remove_invalid_child( $node );
+			} else {
+				$node->parentNode->replaceChild( $new_node, $node );
+			}
+
+			$this->did_convert_elements = true;
+
+		}
+	}
+
+	/**
+	 * Filter video dimensions, try to get width and height from original file if missing.
+	 *
+	 * @param array  $new_attributes Attributes.
+	 * @param string $src            Video URL.
+	 * @return array Modified attributes.
+	 */
+	protected function filter_video_dimensions( $new_attributes, $src ) {
+		if ( empty( $new_attributes['width'] ) || empty( $new_attributes['height'] ) ) {
+
+			// Get the width and height from the file.
+			$path = wp_parse_url( $src, PHP_URL_PATH );
+			$ext  = pathinfo( $path, PATHINFO_EXTENSION );
+			$name = sanitize_title( wp_basename( $path, ".$ext" ) );
+			$args = array(
+				'name'        => $name,
+				'post_type'   => 'attachment',
+				'post_status' => 'inherit',
+				'numberposts' => 1,
+			);
+
+			$attachment = get_posts( $args );
+
+			if ( ! empty( $attachment ) ) {
+				$meta_data = wp_get_attachment_metadata( $attachment[0]->ID );
+				if ( empty( $new_attributes['width'] ) && ! empty( $meta_data['width'] ) ) {
+					$new_attributes['width'] = $meta_data['width'];
+				}
+				if ( empty( $new_attributes['height'] ) && ! empty( $meta_data['height'] ) ) {
+					$new_attributes['height'] = $meta_data['height'];
+				}
+			}
+		}
+
+		return $new_attributes;
+	}
+
+	/**
+	 * "Filter" HTML attributes for <amp-audio> elements.
+	 *
+	 * @since 0.2
+	 * @since 1.0 Force HTTPS for the src attribute.
+	 *
+	 * @param string[] $attributes {
+	 *      Attributes.
+	 *
+	 *      @type string    $src        Video URL - Empty if HTTPS required per $this->args['require_https_src']
+	 *      @type int       $width      <video> attribute - Set to numeric value if px or %
+	 *      @type int       $height     <video> attribute - Set to numeric value if px or %
+	 *      @type string    $poster     <video> attribute - Pass along if found
+	 *      @type string    $class      <video> attribute - Pass along if found
+	 *      @type bool      $controls   <video> attribute - Convert 'false' to empty string ''
+	 *      @type bool      $loop       <video> attribute - Convert 'false' to empty string ''
+	 *      @type bool      $muted      <video> attribute - Convert 'false' to empty string ''
+	 *      @type bool      $autoplay   <video> attribute - Convert 'false' to empty string ''
+	 * }
+	 * @return array Returns HTML attributes; removes any not specifically declared above from input.
+	 */
+	private function filter_attributes( $attributes ) {
+		$out = array();
+
+		foreach ( $attributes as $name => $value ) {
+			switch ( $name ) {
+				case 'src':
+					$out[ $name ] = $this->maybe_enforce_https_src( $value, true );
+					break;
+
+				case 'width':
+				case 'height':
+					$out[ $name ] = $this->sanitize_dimension( $value, $name );
+					break;
+
+				// @todo Convert to HTTPS when is_ssl().
+				case 'poster':
+				case 'artwork':
+					$out[ $name ] = $value;
+					break;
+
+				case 'controls':
+				case 'loop':
+				case 'muted':
+				case 'autoplay':
+					if ( 'false' !== $value ) {
+						$out[ $name ] = '';
+					}
+					break;
+
+				case 'data-amp-layout':
+					$out['layout'] = $value;
+					break;
+
+				case 'data-amp-noloading':
+					$out['noloading'] = $value;
+					break;
+
+				default:
+					$out[ $name ] = $value;
+			}
+		}
+
+		return $out;
+	}
+}

From 2346234400b51c254adf3e613eae59abc6e08928 Mon Sep 17 00:00:00 2001
From: Marcelo Vani <marcellovani@yahoo.co.uk>
Date: Thu, 29 Nov 2018 16:39:47 +0000
Subject: [PATCH 09/17] Use autoloader

---
 amp.php       |  1 +
 composer.lock | 12 ++++++------
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/amp.php b/amp.php
index d3cb0c0e44f..f515e20a34a 100644
--- a/amp.php
+++ b/amp.php
@@ -96,6 +96,7 @@ function _amp_incorrect_plugin_slug_admin_notice() {
 	add_action( 'admin_notices', '_amp_incorrect_plugin_slug_admin_notice' );
 }
 
+require_once AMP__DIR__ . '/vendor/autoload.php';
 require_once AMP__DIR__ . '/includes/class-amp-autoloader.php';
 AMP_Autoloader::register();
 
diff --git a/composer.lock b/composer.lock
index 9731eaf8f8f..d85ec3aa2ac 100644
--- a/composer.lock
+++ b/composer.lock
@@ -12,12 +12,12 @@
             "source": {
                 "type": "git",
                 "url": "https://github.com/marcelovani/amp-sanitizer.git",
-                "reference": "16b5d0d8695a708f3f27c0cd1a183bc8721e80ba"
+                "reference": "b933b4ef6e79c3e3ef336f88f4132bd86e1039a3"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/marcelovani/amp-sanitizer/zipball/16b5d0d8695a708f3f27c0cd1a183bc8721e80ba",
-                "reference": "16b5d0d8695a708f3f27c0cd1a183bc8721e80ba",
+                "url": "https://api.github.com/repos/marcelovani/amp-sanitizer/zipball/b933b4ef6e79c3e3ef336f88f4132bd86e1039a3",
+                "reference": "b933b4ef6e79c3e3ef336f88f4132bd86e1039a3",
                 "shasum": ""
             },
             "require": {
@@ -31,8 +31,8 @@
             },
             "type": "library",
             "autoload": {
-                "psr-4": {
-                    "": "includes/sanitizers"
+                "files": {
+                    "AMP_Allowed_Tags_Generated": "includes/sanitizers/class-amp-allowed-tags-generated.php"
                 }
             },
             "notification-url": "https://packagist.org/downloads/",
@@ -41,7 +41,7 @@
             ],
             "description": "Consumes AMPHtml rules and generates AMP sanitizers",
             "homepage": "https://github.com/marcelovani/amp-sanitizer",
-            "time": "2018-11-29T15:33:45+00:00"
+            "time": "2018-11-29T16:31:50+00:00"
         },
         {
             "name": "sabberworm/php-css-parser",

From 2cc322b58be452b4fab6555e899783e3d75c98c8 Mon Sep 17 00:00:00 2001
From: Marcelo Vani <marcellovani@yahoo.co.uk>
Date: Wed, 5 Dec 2018 23:54:39 +0000
Subject: [PATCH 10/17] Resolving dependencies

---
 composer.json |   8 +-
 composer.lock | 566 +++++++++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 546 insertions(+), 28 deletions(-)

diff --git a/composer.json b/composer.json
index e07f32fbca3..9fd5e5b4032 100644
--- a/composer.json
+++ b/composer.json
@@ -8,13 +8,17 @@
         {
             "type": "vcs",
             "url": "https://github.com/xwp/PHP-CSS-Parser"
+        },
+        {
+            "type": "vcs",
+            "url": "git@github.com:dennisinteractive/amp-library.git"
         }
     ],
     "require": {
         "php": "^5.3.6 || ^7.0",
-        "sabberworm/php-css-parser": "dev-master",
+        "sabberworm/php-css-parser": "dev-master as 8.0.0",
         "xwp/wp-dev-lib": "dev-master",
-        "marcelovani/amp-sanitizer": "dev-master"
+        "lullabot/amp": "dev-amphtml-generator"
     },
     "require-dev": {
         "wp-coding-standards/wpcs": "^0.14.0",
diff --git a/composer.lock b/composer.lock
index d85ec3aa2ac..33927c44662 100644
--- a/composer.lock
+++ b/composer.lock
@@ -1,47 +1,502 @@
 {
     "_readme": [
         "This file locks the dependencies of your project to a known state",
-        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
+        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
         "This file is @generated automatically"
     ],
-    "content-hash": "aa0fbfa002263abe1019d76833748b0f",
+    "content-hash": "6a971dda899a601da9d343184cf08027",
     "packages": [
         {
-            "name": "marcelovani/amp-sanitizer",
-            "version": "dev-master",
+            "name": "guzzlehttp/guzzle",
+            "version": "6.3.3",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/guzzle/guzzle.git",
+                "reference": "407b0cb880ace85c9b63c5f9551db498cb2d50ba"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/guzzle/guzzle/zipball/407b0cb880ace85c9b63c5f9551db498cb2d50ba",
+                "reference": "407b0cb880ace85c9b63c5f9551db498cb2d50ba",
+                "shasum": ""
+            },
+            "require": {
+                "guzzlehttp/promises": "^1.0",
+                "guzzlehttp/psr7": "^1.4",
+                "php": ">=5.5"
+            },
+            "require-dev": {
+                "ext-curl": "*",
+                "phpunit/phpunit": "^4.8.35 || ^5.7 || ^6.4 || ^7.0",
+                "psr/log": "^1.0"
+            },
+            "suggest": {
+                "psr/log": "Required for using the Log middleware"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "6.3-dev"
+                }
+            },
+            "autoload": {
+                "files": [
+                    "src/functions_include.php"
+                ],
+                "psr-4": {
+                    "GuzzleHttp\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Michael Dowling",
+                    "email": "mtdowling@gmail.com",
+                    "homepage": "https://github.com/mtdowling"
+                }
+            ],
+            "description": "Guzzle is a PHP HTTP client library",
+            "homepage": "http://guzzlephp.org/",
+            "keywords": [
+                "client",
+                "curl",
+                "framework",
+                "http",
+                "http client",
+                "rest",
+                "web service"
+            ],
+            "time": "2018-04-22T15:46:56+00:00"
+        },
+        {
+            "name": "guzzlehttp/promises",
+            "version": "v1.3.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/guzzle/promises.git",
+                "reference": "a59da6cf61d80060647ff4d3eb2c03a2bc694646"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/guzzle/promises/zipball/a59da6cf61d80060647ff4d3eb2c03a2bc694646",
+                "reference": "a59da6cf61d80060647ff4d3eb2c03a2bc694646",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.5.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "^4.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.4-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "GuzzleHttp\\Promise\\": "src/"
+                },
+                "files": [
+                    "src/functions_include.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Michael Dowling",
+                    "email": "mtdowling@gmail.com",
+                    "homepage": "https://github.com/mtdowling"
+                }
+            ],
+            "description": "Guzzle promises library",
+            "keywords": [
+                "promise"
+            ],
+            "time": "2016-12-20T10:07:11+00:00"
+        },
+        {
+            "name": "guzzlehttp/psr7",
+            "version": "1.5.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/guzzle/psr7.git",
+                "reference": "9f83dded91781a01c63574e387eaa769be769115"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/guzzle/psr7/zipball/9f83dded91781a01c63574e387eaa769be769115",
+                "reference": "9f83dded91781a01c63574e387eaa769be769115",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.4.0",
+                "psr/http-message": "~1.0",
+                "ralouphie/getallheaders": "^2.0.5"
+            },
+            "provide": {
+                "psr/http-message-implementation": "1.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "~4.8.36 || ^5.7.27 || ^6.5.8"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.5-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "GuzzleHttp\\Psr7\\": "src/"
+                },
+                "files": [
+                    "src/functions_include.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Michael Dowling",
+                    "email": "mtdowling@gmail.com",
+                    "homepage": "https://github.com/mtdowling"
+                },
+                {
+                    "name": "Tobias Schultze",
+                    "homepage": "https://github.com/Tobion"
+                }
+            ],
+            "description": "PSR-7 message implementation that also provides common utility methods",
+            "keywords": [
+                "http",
+                "message",
+                "psr-7",
+                "request",
+                "response",
+                "stream",
+                "uri",
+                "url"
+            ],
+            "time": "2018-12-04T20:46:45+00:00"
+        },
+        {
+            "name": "lullabot/amp",
+            "version": "dev-amphtml-generator",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/dennisinteractive/amp-library.git",
+                "reference": "016288eab7778063a0be9019c8aa696b69119824"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/dennisinteractive/amp-library/zipball/016288eab7778063a0be9019c8aa696b69119824",
+                "reference": "016288eab7778063a0be9019c8aa696b69119824",
+                "shasum": ""
+            },
+            "require": {
+                "guzzlehttp/guzzle": "~6.1",
+                "marc1706/fast-image-size": "1.*",
+                "masterminds/html5": "~2.0",
+                "php": ">=5.5.0",
+                "querypath/querypath": ">=3.0.4",
+                "sabberworm/php-css-parser": "^8.0.0",
+                "sebastian/diff": "^1.2 || ^2 || ^3"
+            },
+            "require-dev": {
+                "php": ">=5.5.0",
+                "phpunit/phpunit": "4.8.* || ^6",
+                "symfony/console": "^2.7.0"
+            },
+            "type": "library",
+            "autoload": {
+                "classmap": [
+                    "src/Spec/validator-generated.php"
+                ],
+                "psr-4": {
+                    "Lullabot\\AMP\\": "src"
+                }
+            },
+            "license": [
+                "Apache-2.0"
+            ],
+            "authors": [
+                {
+                    "name": "Sidharth Kshatriya",
+                    "email": "sid.kshatriya@gmail.com"
+                }
+            ],
+            "description": "A set of useful classes and utilities to convert html to AMP html (See https://www.ampproject.org/)",
+            "homepage": "https://github.com/Lullabot/amp-library",
+            "keywords": [
+                "AMP",
+                "Drupal",
+                "mobile"
+            ],
+            "support": {
+                "source": "https://github.com/dennisinteractive/amp-library/tree/amphtml-generator"
+            },
+            "time": "2018-12-05 23:41:16"
+        },
+        {
+            "name": "marc1706/fast-image-size",
+            "version": "v1.1.4",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/marc1706/fast-image-size.git",
+                "reference": "c4ded0223a4e49ae45a2183a69f6afac5baf7250"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/marc1706/fast-image-size/zipball/c4ded0223a4e49ae45a2183a69f6afac5baf7250",
+                "reference": "c4ded0223a4e49ae45a2183a69f6afac5baf7250",
+                "shasum": ""
+            },
+            "require": {
+                "ext-mbstring": "*",
+                "php": ">=5.3.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "4.*"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "FastImageSize\\": "lib",
+                    "FastImageSize\\tests\\": "tests"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Marc Alexander",
+                    "email": "admin@m-a-styles.de",
+                    "homepage": "https://www.m-a-styles.de",
+                    "role": "Developer"
+                }
+            ],
+            "description": "fast-image-size is a PHP library that does almost everything PHP's getimagesize() does but without the large overhead of downloading the complete file.",
+            "homepage": "https://www.m-a-styles.de",
+            "keywords": [
+                "fast",
+                "getimagesize",
+                "image",
+                "imagesize",
+                "php",
+                "size"
+            ],
+            "time": "2017-10-23T18:52:01+00:00"
+        },
+        {
+            "name": "masterminds/html5",
+            "version": "2.4.0",
             "source": {
                 "type": "git",
-                "url": "https://github.com/marcelovani/amp-sanitizer.git",
-                "reference": "b933b4ef6e79c3e3ef336f88f4132bd86e1039a3"
+                "url": "https://github.com/Masterminds/html5-php.git",
+                "reference": "cadcfaaa13153e0e8eb92c49a53e140cf1a85dea"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/marcelovani/amp-sanitizer/zipball/b933b4ef6e79c3e3ef336f88f4132bd86e1039a3",
-                "reference": "b933b4ef6e79c3e3ef336f88f4132bd86e1039a3",
+                "url": "https://api.github.com/repos/Masterminds/html5-php/zipball/cadcfaaa13153e0e8eb92c49a53e140cf1a85dea",
+                "reference": "cadcfaaa13153e0e8eb92c49a53e140cf1a85dea",
                 "shasum": ""
             },
             "require": {
-                "php": "^5.3.6 || ^7.0"
+                "ext-ctype": "*",
+                "ext-dom": "*",
+                "ext-libxml": "*",
+                "php": ">=5.3.0"
             },
             "require-dev": {
-                "dealerdirect/phpcodesniffer-composer-installer": "^0.4.4",
-                "sabberworm/php-css-parser": "dev-master",
-                "wimg/php-compatibility": "^8.1",
-                "wp-coding-standards/wpcs": "^0.14.0"
+                "phpunit/phpunit": "4.*",
+                "sami/sami": "~2.0",
+                "satooshi/php-coveralls": "1.0.*"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "2.2-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Masterminds\\": "src"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Matt Butcher",
+                    "email": "technosophos@gmail.com"
+                },
+                {
+                    "name": "Asmir Mustafic",
+                    "email": "goetas@gmail.com"
+                },
+                {
+                    "name": "Matt Farina",
+                    "email": "matt@mattfarina.com"
+                }
+            ],
+            "description": "An HTML5 parser and serializer.",
+            "homepage": "http://masterminds.github.io/html5-php",
+            "keywords": [
+                "HTML5",
+                "dom",
+                "html",
+                "parser",
+                "querypath",
+                "serializer",
+                "xml"
+            ],
+            "time": "2018-11-17T20:24:36+00:00"
+        },
+        {
+            "name": "psr/http-message",
+            "version": "1.0.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/php-fig/http-message.git",
+                "reference": "f6561bf28d520154e4b0ec72be95418abe6d9363"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/php-fig/http-message/zipball/f6561bf28d520154e4b0ec72be95418abe6d9363",
+                "reference": "f6561bf28d520154e4b0ec72be95418abe6d9363",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.3.0"
             },
             "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.0.x-dev"
+                }
+            },
             "autoload": {
-                "files": {
-                    "AMP_Allowed_Tags_Generated": "includes/sanitizers/class-amp-allowed-tags-generated.php"
+                "psr-4": {
+                    "Psr\\Http\\Message\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "PHP-FIG",
+                    "homepage": "http://www.php-fig.org/"
                 }
+            ],
+            "description": "Common interface for HTTP messages",
+            "homepage": "https://github.com/php-fig/http-message",
+            "keywords": [
+                "http",
+                "http-message",
+                "psr",
+                "psr-7",
+                "request",
+                "response"
+            ],
+            "time": "2016-08-06T14:39:51+00:00"
+        },
+        {
+            "name": "querypath/querypath",
+            "version": "3.0.5",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/technosophos/querypath.git",
+                "reference": "6b8e2395fac61fac25bbe962f94def556cb85f7d"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/technosophos/querypath/zipball/6b8e2395fac61fac25bbe962f94def556cb85f7d",
+                "reference": "6b8e2395fac61fac25bbe962f94def556cb85f7d",
+                "shasum": ""
+            },
+            "require": {
+                "masterminds/html5": "2.*",
+                "php": ">=5.3.0"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-0": {
+                    "QueryPath": "src/"
+                },
+                "files": [
+                    "src/qp_functions.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "description": "HTML/XML querying (CSS 4 or XPath) and processing (like jQuery)",
+            "homepage": "https://github.com/technosophos/querypath",
+            "keywords": [
+                "css",
+                "html",
+                "jquery",
+                "xml",
+                "xslt"
+            ],
+            "time": "2016-08-01T22:40:30+00:00"
+        },
+        {
+            "name": "ralouphie/getallheaders",
+            "version": "2.0.5",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/ralouphie/getallheaders.git",
+                "reference": "5601c8a83fbba7ef674a7369456d12f1e0d0eafa"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/ralouphie/getallheaders/zipball/5601c8a83fbba7ef674a7369456d12f1e0d0eafa",
+                "reference": "5601c8a83fbba7ef674a7369456d12f1e0d0eafa",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.3"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "~3.7.0",
+                "satooshi/php-coveralls": ">=1.0"
+            },
+            "type": "library",
+            "autoload": {
+                "files": [
+                    "src/getallheaders.php"
+                ]
             },
             "notification-url": "https://packagist.org/downloads/",
             "license": [
-                "GPL-2.0"
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Ralph Khattar",
+                    "email": "ralph.khattar@gmail.com"
+                }
             ],
-            "description": "Consumes AMPHtml rules and generates AMP sanitizers",
-            "homepage": "https://github.com/marcelovani/amp-sanitizer",
-            "time": "2018-11-29T16:31:50+00:00"
+            "description": "A polyfill for getallheaders.",
+            "time": "2016-02-11T07:05:27+00:00"
         },
         {
             "name": "sabberworm/php-css-parser",
@@ -87,7 +542,59 @@
             "support": {
                 "source": "https://github.com/xwp/PHP-CSS-Parser/tree/master"
             },
-            "time": "2018-11-25T04:50:29+00:00"
+            "time": "2018-11-25 04:50:29"
+        },
+        {
+            "name": "sebastian/diff",
+            "version": "1.4.3",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/sebastianbergmann/diff.git",
+                "reference": "7f066a26a962dbe58ddea9f72a4e82874a3975a4"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/sebastianbergmann/diff/zipball/7f066a26a962dbe58ddea9f72a4e82874a3975a4",
+                "reference": "7f066a26a962dbe58ddea9f72a4e82874a3975a4",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^5.3.3 || ^7.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "^4.8.35 || ^5.7 || ^6.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.4-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Kore Nordmann",
+                    "email": "mail@kore-nordmann.de"
+                },
+                {
+                    "name": "Sebastian Bergmann",
+                    "email": "sebastian@phpunit.de"
+                }
+            ],
+            "description": "Diff implementation",
+            "homepage": "https://github.com/sebastianbergmann/diff",
+            "keywords": [
+                "diff"
+            ],
+            "time": "2017-05-22T07:24:03+00:00"
         },
         {
             "name": "xwp/wp-dev-lib",
@@ -95,12 +602,12 @@
             "source": {
                 "type": "git",
                 "url": "https://github.com/xwp/wp-dev-lib.git",
-                "reference": "ff2cfd2dfbf42360d70b38089d31eaeefd715146"
+                "reference": "c21a863b8ec6d13568c8751db8bd68203d57dd57"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/xwp/wp-dev-lib/zipball/ff2cfd2dfbf42360d70b38089d31eaeefd715146",
-                "reference": "ff2cfd2dfbf42360d70b38089d31eaeefd715146",
+                "url": "https://api.github.com/repos/xwp/wp-dev-lib/zipball/c21a863b8ec6d13568c8751db8bd68203d57dd57",
+                "reference": "c21a863b8ec6d13568c8751db8bd68203d57dd57",
                 "shasum": ""
             },
             "type": "library",
@@ -125,7 +632,7 @@
             "keywords": [
                 "wordpress"
             ],
-            "time": "2018-11-22T04:47:01+00:00"
+            "time": "2018-12-04 22:42:36"
         }
     ],
     "packages-dev": [
@@ -342,12 +849,19 @@
             "time": "2018-02-16T01:57:48+00:00"
         }
     ],
-    "aliases": [],
+    "aliases": [
+        {
+            "alias": "8.0.0",
+            "alias_normalized": "8.0.0.0",
+            "version": "9999999-dev",
+            "package": "sabberworm/php-css-parser"
+        }
+    ],
     "minimum-stability": "stable",
     "stability-flags": {
         "sabberworm/php-css-parser": 20,
         "xwp/wp-dev-lib": 20,
-        "marcelovani/amp-sanitizer": 20
+        "lullabot/amp": 20
     },
     "prefer-stable": false,
     "prefer-lowest": false,

From d37e8c36fd81bf79594c2b4c0e7a7fdcfa4d52fd Mon Sep 17 00:00:00 2001
From: Marcelo <marcellovani@yahoo.co.uk>
Date: Wed, 5 Dec 2018 23:57:33 +0000
Subject: [PATCH 11/17] Reverted commit

---
 bin/create-gutenberg-test-post.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/bin/create-gutenberg-test-post.sh b/bin/create-gutenberg-test-post.sh
index a2513887110..1c719dac00c 100644
--- a/bin/create-gutenberg-test-post.sh
+++ b/bin/create-gutenberg-test-post.sh
@@ -13,7 +13,7 @@ if [[ ! -e $GUTENBERG_PATH ]]; then
 	echo "This needs to clone the Gutenberg plugin into your plugins directory, as it looks like it's not there."
 	read -p "Is that alright? y/n " -r
 	if [[ $REPLY =~ [Yy] ]]; then
-		git clone --depth=1 https://github.com/WordPress/gutenberg.git
+		git clone https://github.com/WordPress/gutenberg.git
 		wp plugin activate gutenberg
 		echo "The Gutenberg plugin is cloned. Please follow the build steps:"
 		echo "https://github.com/WordPress/gutenberg/blob/master/CONTRIBUTING.md"

From 17d337cf1f04254da56723b1fa2df0e1fe4237db Mon Sep 17 00:00:00 2001
From: Marcelo Vani <marcellovani@yahoo.co.uk>
Date: Thu, 6 Dec 2018 00:10:40 +0000
Subject: [PATCH 12/17] Updating dependencies

---
 composer.lock | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/composer.lock b/composer.lock
index 33927c44662..cb1381a0497 100644
--- a/composer.lock
+++ b/composer.lock
@@ -195,12 +195,12 @@
             "source": {
                 "type": "git",
                 "url": "https://github.com/dennisinteractive/amp-library.git",
-                "reference": "016288eab7778063a0be9019c8aa696b69119824"
+                "reference": "bff03d195ffbfd57c746243b4ea34685f6c8022f"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/dennisinteractive/amp-library/zipball/016288eab7778063a0be9019c8aa696b69119824",
-                "reference": "016288eab7778063a0be9019c8aa696b69119824",
+                "url": "https://api.github.com/repos/dennisinteractive/amp-library/zipball/bff03d195ffbfd57c746243b4ea34685f6c8022f",
+                "reference": "bff03d195ffbfd57c746243b4ea34685f6c8022f",
                 "shasum": ""
             },
             "require": {
@@ -220,7 +220,7 @@
             "type": "library",
             "autoload": {
                 "classmap": [
-                    "src/Spec/validator-generated.php"
+                    "src/Spec"
                 ],
                 "psr-4": {
                     "Lullabot\\AMP\\": "src"
@@ -245,7 +245,7 @@
             "support": {
                 "source": "https://github.com/dennisinteractive/amp-library/tree/amphtml-generator"
             },
-            "time": "2018-12-05 23:41:16"
+            "time": "2018-12-06 00:08:47"
         },
         {
             "name": "marc1706/fast-image-size",

From b23559c433235114f0734a4589d50bb606aee9d1 Mon Sep 17 00:00:00 2001
From: Marcelo Vani <marcellovani@yahoo.co.uk>
Date: Thu, 6 Dec 2018 11:33:51 +0000
Subject: [PATCH 13/17] Use Lullabot AMP library to convert the page

---
 includes/templates/class-amp-post-template.php | 15 +++++++++++++++
 templates/single.php                           |  7 ++++++-
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/includes/templates/class-amp-post-template.php b/includes/templates/class-amp-post-template.php
index 1e4fa103ad2..337459ce2da 100644
--- a/includes/templates/class-amp-post-template.php
+++ b/includes/templates/class-amp-post-template.php
@@ -315,6 +315,21 @@ private function build_post_commments_data() {
 	 * Build post content.
 	 */
 	private function build_post_content() {
+    $amp = new \Lullabot\AMP\AMP();
+
+    $content = apply_filters('the_content', $this->post->post_content);
+
+    $options = array(
+      'scope' => 'body',
+      'add_stats_html_comment' => false
+    );
+    $amp->loadHtml($content, $options);
+
+    $this->add_data_by_key('post_amp_content', $amp->convertToAmpHtml());
+    $this->merge_data_for_key('amp_component_scripts', $amp->getComponentJs());
+    $this->add_data_by_key('post_amp_debug', $amp->warningsHumanHtml());
+    return;
+
 		$amp_content = new AMP_Content(
 			$this->post->post_content,
 			amp_get_content_embed_handlers( $this->post ),
diff --git a/templates/single.php b/templates/single.php
index 6a6c883476d..4887d0627fd 100644
--- a/templates/single.php
+++ b/templates/single.php
@@ -26,7 +26,12 @@
 
 	<div class="amp-wp-article-content">
 		<?php echo $this->get( 'post_amp_content' ); // WPCS: XSS ok. Handled in AMP_Content::transform(). ?>
-	</div>
+    </div>
+    <div class="debug">
+        <pre>
+            <?php echo $this->get( 'post_amp_debug' ); ?>
+        </pre>
+    </div>
 
 	<footer class="amp-wp-article-footer">
 		<?php $this->load_parts( apply_filters( 'amp_post_article_footer_meta', array( 'meta-taxonomy', 'meta-comments-link' ) ) ); ?>

From e2822a06c866da0d8575d85feaec99583e07e4ba Mon Sep 17 00:00:00 2001
From: Marcelo Vani <marcellovani@yahoo.co.uk>
Date: Thu, 6 Dec 2018 16:27:06 +0000
Subject: [PATCH 14/17] Require symfony/console

---
 composer.json |   5 +-
 composer.lock | 245 ++++++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 242 insertions(+), 8 deletions(-)

diff --git a/composer.json b/composer.json
index 9fd5e5b4032..71093e96bc3 100644
--- a/composer.json
+++ b/composer.json
@@ -4,6 +4,8 @@
     "homepage": "https://github.com/Automattic/amp-wp",
     "type": "wordpress-plugin",
     "license": "GPL-2.0",
+    "minimum-stability": "dev",
+    "prefer-stable": true,
     "repositories": [
         {
             "type": "vcs",
@@ -18,7 +20,8 @@
         "php": "^5.3.6 || ^7.0",
         "sabberworm/php-css-parser": "dev-master as 8.0.0",
         "xwp/wp-dev-lib": "dev-master",
-        "lullabot/amp": "dev-amphtml-generator"
+        "lullabot/amp": "dev-amphtml-generator",
+        "symfony/console": "^3.4"
     },
     "require-dev": {
         "wp-coding-standards/wpcs": "^0.14.0",
diff --git a/composer.lock b/composer.lock
index cb1381a0497..41a436bfb61 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
         "This file is @generated automatically"
     ],
-    "content-hash": "6a971dda899a601da9d343184cf08027",
+    "content-hash": "ececfe8594daffc40999ee86769921eb",
     "packages": [
         {
             "name": "guzzlehttp/guzzle",
@@ -195,12 +195,12 @@
             "source": {
                 "type": "git",
                 "url": "https://github.com/dennisinteractive/amp-library.git",
-                "reference": "bff03d195ffbfd57c746243b4ea34685f6c8022f"
+                "reference": "2d0a28ee418db1c4632d0c1fc867c1a0f4fe97ad"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/dennisinteractive/amp-library/zipball/bff03d195ffbfd57c746243b4ea34685f6c8022f",
-                "reference": "bff03d195ffbfd57c746243b4ea34685f6c8022f",
+                "url": "https://api.github.com/repos/dennisinteractive/amp-library/zipball/2d0a28ee418db1c4632d0c1fc867c1a0f4fe97ad",
+                "reference": "2d0a28ee418db1c4632d0c1fc867c1a0f4fe97ad",
                 "shasum": ""
             },
             "require": {
@@ -245,7 +245,7 @@
             "support": {
                 "source": "https://github.com/dennisinteractive/amp-library/tree/amphtml-generator"
             },
-            "time": "2018-12-06 00:08:47"
+            "time": "2018-12-06 01:13:37"
         },
         {
             "name": "marc1706/fast-image-size",
@@ -416,6 +416,53 @@
             ],
             "time": "2016-08-06T14:39:51+00:00"
         },
+        {
+            "name": "psr/log",
+            "version": "1.1.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/php-fig/log.git",
+                "reference": "6c001f1daafa3a3ac1d8ff69ee4db8e799a654dd"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/php-fig/log/zipball/6c001f1daafa3a3ac1d8ff69ee4db8e799a654dd",
+                "reference": "6c001f1daafa3a3ac1d8ff69ee4db8e799a654dd",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.3.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.0.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Psr\\Log\\": "Psr/Log/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "PHP-FIG",
+                    "homepage": "http://www.php-fig.org/"
+                }
+            ],
+            "description": "Common interface for logging libraries",
+            "homepage": "https://github.com/php-fig/log",
+            "keywords": [
+                "log",
+                "psr",
+                "psr-3"
+            ],
+            "time": "2018-11-20T15:27:04+00:00"
+        },
         {
             "name": "querypath/querypath",
             "version": "3.0.5",
@@ -596,6 +643,190 @@
             ],
             "time": "2017-05-22T07:24:03+00:00"
         },
+        {
+            "name": "symfony/console",
+            "version": "v3.4.20",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/console.git",
+                "reference": "8f80fc39bbc3b7c47ee54ba7aa2653521ace94bb"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/console/zipball/8f80fc39bbc3b7c47ee54ba7aa2653521ace94bb",
+                "reference": "8f80fc39bbc3b7c47ee54ba7aa2653521ace94bb",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^5.5.9|>=7.0.8",
+                "symfony/debug": "~2.8|~3.0|~4.0",
+                "symfony/polyfill-mbstring": "~1.0"
+            },
+            "conflict": {
+                "symfony/dependency-injection": "<3.4",
+                "symfony/process": "<3.3"
+            },
+            "require-dev": {
+                "psr/log": "~1.0",
+                "symfony/config": "~3.3|~4.0",
+                "symfony/dependency-injection": "~3.4|~4.0",
+                "symfony/event-dispatcher": "~2.8|~3.0|~4.0",
+                "symfony/lock": "~3.4|~4.0",
+                "symfony/process": "~3.3|~4.0"
+            },
+            "suggest": {
+                "psr/log-implementation": "For using the console logger",
+                "symfony/event-dispatcher": "",
+                "symfony/lock": "",
+                "symfony/process": ""
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "3.4-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Symfony\\Component\\Console\\": ""
+                },
+                "exclude-from-classmap": [
+                    "/Tests/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Fabien Potencier",
+                    "email": "fabien@symfony.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "Symfony Console Component",
+            "homepage": "https://symfony.com",
+            "time": "2018-11-26T12:48:07+00:00"
+        },
+        {
+            "name": "symfony/debug",
+            "version": "v3.4.20",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/debug.git",
+                "reference": "a2233f555ddf55e5600f386fba7781cea1cb82d3"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/debug/zipball/a2233f555ddf55e5600f386fba7781cea1cb82d3",
+                "reference": "a2233f555ddf55e5600f386fba7781cea1cb82d3",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^5.5.9|>=7.0.8",
+                "psr/log": "~1.0"
+            },
+            "conflict": {
+                "symfony/http-kernel": ">=2.3,<2.3.24|~2.4.0|>=2.5,<2.5.9|>=2.6,<2.6.2"
+            },
+            "require-dev": {
+                "symfony/http-kernel": "~2.8|~3.0|~4.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "3.4-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Symfony\\Component\\Debug\\": ""
+                },
+                "exclude-from-classmap": [
+                    "/Tests/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Fabien Potencier",
+                    "email": "fabien@symfony.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "Symfony Debug Component",
+            "homepage": "https://symfony.com",
+            "time": "2018-11-27T12:43:10+00:00"
+        },
+        {
+            "name": "symfony/polyfill-mbstring",
+            "version": "v1.10.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/polyfill-mbstring.git",
+                "reference": "c79c051f5b3a46be09205c73b80b346e4153e494"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/polyfill-mbstring/zipball/c79c051f5b3a46be09205c73b80b346e4153e494",
+                "reference": "c79c051f5b3a46be09205c73b80b346e4153e494",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.3.3"
+            },
+            "suggest": {
+                "ext-mbstring": "For best performance"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.9-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Symfony\\Polyfill\\Mbstring\\": ""
+                },
+                "files": [
+                    "bootstrap.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Nicolas Grekas",
+                    "email": "p@tchwork.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "Symfony polyfill for the Mbstring extension",
+            "homepage": "https://symfony.com",
+            "keywords": [
+                "compatibility",
+                "mbstring",
+                "polyfill",
+                "portable",
+                "shim"
+            ],
+            "time": "2018-09-21T13:07:52+00:00"
+        },
         {
             "name": "xwp/wp-dev-lib",
             "version": "dev-master",
@@ -857,13 +1088,13 @@
             "package": "sabberworm/php-css-parser"
         }
     ],
-    "minimum-stability": "stable",
+    "minimum-stability": "dev",
     "stability-flags": {
         "sabberworm/php-css-parser": 20,
         "xwp/wp-dev-lib": 20,
         "lullabot/amp": 20
     },
-    "prefer-stable": false,
+    "prefer-stable": true,
     "prefer-lowest": false,
     "platform": {
         "php": "^5.3.6 || ^7.0"

From 1c43343409630909e1a93cd80b22cb7bdb2855f4 Mon Sep 17 00:00:00 2001
From: Marcelo Vani <marcellovani@yahoo.co.uk>
Date: Thu, 6 Dec 2018 16:36:30 +0000
Subject: [PATCH 15/17] Updated packages

---
 composer.lock | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/composer.lock b/composer.lock
index 41a436bfb61..3e5dc462a09 100644
--- a/composer.lock
+++ b/composer.lock
@@ -195,12 +195,12 @@
             "source": {
                 "type": "git",
                 "url": "https://github.com/dennisinteractive/amp-library.git",
-                "reference": "2d0a28ee418db1c4632d0c1fc867c1a0f4fe97ad"
+                "reference": "14ef6878aef38aa96686ce0f0a50c9bfc8b2b3c3"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/dennisinteractive/amp-library/zipball/2d0a28ee418db1c4632d0c1fc867c1a0f4fe97ad",
-                "reference": "2d0a28ee418db1c4632d0c1fc867c1a0f4fe97ad",
+                "url": "https://api.github.com/repos/dennisinteractive/amp-library/zipball/14ef6878aef38aa96686ce0f0a50c9bfc8b2b3c3",
+                "reference": "14ef6878aef38aa96686ce0f0a50c9bfc8b2b3c3",
                 "shasum": ""
             },
             "require": {
@@ -245,7 +245,7 @@
             "support": {
                 "source": "https://github.com/dennisinteractive/amp-library/tree/amphtml-generator"
             },
-            "time": "2018-12-06 01:13:37"
+            "time": "2018-12-06 16:28:28"
         },
         {
             "name": "marc1706/fast-image-size",

From 20389ccfaa7181fadc70780270313fef723a789b Mon Sep 17 00:00:00 2001
From: Marcelo Vani <marcellovani@yahoo.co.uk>
Date: Fri, 7 Dec 2018 09:47:04 +0000
Subject: [PATCH 16/17] Upgraded composer

---
 amp.php       |  1 -
 composer.lock | 17 ++++++++++-------
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/amp.php b/amp.php
index f515e20a34a..d3cb0c0e44f 100644
--- a/amp.php
+++ b/amp.php
@@ -96,7 +96,6 @@ function _amp_incorrect_plugin_slug_admin_notice() {
 	add_action( 'admin_notices', '_amp_incorrect_plugin_slug_admin_notice' );
 }
 
-require_once AMP__DIR__ . '/vendor/autoload.php';
 require_once AMP__DIR__ . '/includes/class-amp-autoloader.php';
 AMP_Autoloader::register();
 
diff --git a/composer.lock b/composer.lock
index 3e5dc462a09..f931c2741db 100644
--- a/composer.lock
+++ b/composer.lock
@@ -1,7 +1,7 @@
 {
     "_readme": [
         "This file locks the dependencies of your project to a known state",
-        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
+        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
     "content-hash": "ececfe8594daffc40999ee86769921eb",
@@ -195,12 +195,12 @@
             "source": {
                 "type": "git",
                 "url": "https://github.com/dennisinteractive/amp-library.git",
-                "reference": "14ef6878aef38aa96686ce0f0a50c9bfc8b2b3c3"
+                "reference": "9d43a701a5ac7773bbc3f74976b0ed176631c7e7"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/dennisinteractive/amp-library/zipball/14ef6878aef38aa96686ce0f0a50c9bfc8b2b3c3",
-                "reference": "14ef6878aef38aa96686ce0f0a50c9bfc8b2b3c3",
+                "url": "https://api.github.com/repos/dennisinteractive/amp-library/zipball/9d43a701a5ac7773bbc3f74976b0ed176631c7e7",
+                "reference": "9d43a701a5ac7773bbc3f74976b0ed176631c7e7",
                 "shasum": ""
             },
             "require": {
@@ -217,6 +217,9 @@
                 "phpunit/phpunit": "4.8.* || ^6",
                 "symfony/console": "^2.7.0"
             },
+            "bin": [
+                "bin/amp-console"
+            ],
             "type": "library",
             "autoload": {
                 "classmap": [
@@ -245,7 +248,7 @@
             "support": {
                 "source": "https://github.com/dennisinteractive/amp-library/tree/amphtml-generator"
             },
-            "time": "2018-12-06 16:28:28"
+            "time": "2018-12-07T08:53:09+00:00"
         },
         {
             "name": "marc1706/fast-image-size",
@@ -589,7 +592,7 @@
             "support": {
                 "source": "https://github.com/xwp/PHP-CSS-Parser/tree/master"
             },
-            "time": "2018-11-25 04:50:29"
+            "time": "2018-11-25T04:50:29+00:00"
         },
         {
             "name": "sebastian/diff",
@@ -863,7 +866,7 @@
             "keywords": [
                 "wordpress"
             ],
-            "time": "2018-12-04 22:42:36"
+            "time": "2018-12-04T22:42:36+00:00"
         }
     ],
     "packages-dev": [

From 0b20922dd401952aef28de31a159f1a41ab5345c Mon Sep 17 00:00:00 2001
From: Marcelo Vani <marcellovani@yahoo.co.uk>
Date: Fri, 7 Dec 2018 10:32:57 +0000
Subject: [PATCH 17/17] Removed composer.lock

---
 .gitignore    |    2 +
 composer.lock | 1106 -------------------------------------------------
 2 files changed, 2 insertions(+), 1106 deletions(-)
 delete mode 100644 composer.lock

diff --git a/.gitignore b/.gitignore
index 57a64b86765..2ee833aec70 100644
--- a/.gitignore
+++ b/.gitignore
@@ -8,3 +8,5 @@ amp.zip
 languages/*.pot
 languages/*.php
 built
+composer.lock
+
diff --git a/composer.lock b/composer.lock
deleted file mode 100644
index f931c2741db..00000000000
--- a/composer.lock
+++ /dev/null
@@ -1,1106 +0,0 @@
-{
-    "_readme": [
-        "This file locks the dependencies of your project to a known state",
-        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
-        "This file is @generated automatically"
-    ],
-    "content-hash": "ececfe8594daffc40999ee86769921eb",
-    "packages": [
-        {
-            "name": "guzzlehttp/guzzle",
-            "version": "6.3.3",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/guzzle/guzzle.git",
-                "reference": "407b0cb880ace85c9b63c5f9551db498cb2d50ba"
-            },
-            "dist": {
-                "type": "zip",
-                "url": "https://api.github.com/repos/guzzle/guzzle/zipball/407b0cb880ace85c9b63c5f9551db498cb2d50ba",
-                "reference": "407b0cb880ace85c9b63c5f9551db498cb2d50ba",
-                "shasum": ""
-            },
-            "require": {
-                "guzzlehttp/promises": "^1.0",
-                "guzzlehttp/psr7": "^1.4",
-                "php": ">=5.5"
-            },
-            "require-dev": {
-                "ext-curl": "*",
-                "phpunit/phpunit": "^4.8.35 || ^5.7 || ^6.4 || ^7.0",
-                "psr/log": "^1.0"
-            },
-            "suggest": {
-                "psr/log": "Required for using the Log middleware"
-            },
-            "type": "library",
-            "extra": {
-                "branch-alias": {
-                    "dev-master": "6.3-dev"
-                }
-            },
-            "autoload": {
-                "files": [
-                    "src/functions_include.php"
-                ],
-                "psr-4": {
-                    "GuzzleHttp\\": "src/"
-                }
-            },
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "MIT"
-            ],
-            "authors": [
-                {
-                    "name": "Michael Dowling",
-                    "email": "mtdowling@gmail.com",
-                    "homepage": "https://github.com/mtdowling"
-                }
-            ],
-            "description": "Guzzle is a PHP HTTP client library",
-            "homepage": "http://guzzlephp.org/",
-            "keywords": [
-                "client",
-                "curl",
-                "framework",
-                "http",
-                "http client",
-                "rest",
-                "web service"
-            ],
-            "time": "2018-04-22T15:46:56+00:00"
-        },
-        {
-            "name": "guzzlehttp/promises",
-            "version": "v1.3.1",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/guzzle/promises.git",
-                "reference": "a59da6cf61d80060647ff4d3eb2c03a2bc694646"
-            },
-            "dist": {
-                "type": "zip",
-                "url": "https://api.github.com/repos/guzzle/promises/zipball/a59da6cf61d80060647ff4d3eb2c03a2bc694646",
-                "reference": "a59da6cf61d80060647ff4d3eb2c03a2bc694646",
-                "shasum": ""
-            },
-            "require": {
-                "php": ">=5.5.0"
-            },
-            "require-dev": {
-                "phpunit/phpunit": "^4.0"
-            },
-            "type": "library",
-            "extra": {
-                "branch-alias": {
-                    "dev-master": "1.4-dev"
-                }
-            },
-            "autoload": {
-                "psr-4": {
-                    "GuzzleHttp\\Promise\\": "src/"
-                },
-                "files": [
-                    "src/functions_include.php"
-                ]
-            },
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "MIT"
-            ],
-            "authors": [
-                {
-                    "name": "Michael Dowling",
-                    "email": "mtdowling@gmail.com",
-                    "homepage": "https://github.com/mtdowling"
-                }
-            ],
-            "description": "Guzzle promises library",
-            "keywords": [
-                "promise"
-            ],
-            "time": "2016-12-20T10:07:11+00:00"
-        },
-        {
-            "name": "guzzlehttp/psr7",
-            "version": "1.5.2",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/guzzle/psr7.git",
-                "reference": "9f83dded91781a01c63574e387eaa769be769115"
-            },
-            "dist": {
-                "type": "zip",
-                "url": "https://api.github.com/repos/guzzle/psr7/zipball/9f83dded91781a01c63574e387eaa769be769115",
-                "reference": "9f83dded91781a01c63574e387eaa769be769115",
-                "shasum": ""
-            },
-            "require": {
-                "php": ">=5.4.0",
-                "psr/http-message": "~1.0",
-                "ralouphie/getallheaders": "^2.0.5"
-            },
-            "provide": {
-                "psr/http-message-implementation": "1.0"
-            },
-            "require-dev": {
-                "phpunit/phpunit": "~4.8.36 || ^5.7.27 || ^6.5.8"
-            },
-            "type": "library",
-            "extra": {
-                "branch-alias": {
-                    "dev-master": "1.5-dev"
-                }
-            },
-            "autoload": {
-                "psr-4": {
-                    "GuzzleHttp\\Psr7\\": "src/"
-                },
-                "files": [
-                    "src/functions_include.php"
-                ]
-            },
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "MIT"
-            ],
-            "authors": [
-                {
-                    "name": "Michael Dowling",
-                    "email": "mtdowling@gmail.com",
-                    "homepage": "https://github.com/mtdowling"
-                },
-                {
-                    "name": "Tobias Schultze",
-                    "homepage": "https://github.com/Tobion"
-                }
-            ],
-            "description": "PSR-7 message implementation that also provides common utility methods",
-            "keywords": [
-                "http",
-                "message",
-                "psr-7",
-                "request",
-                "response",
-                "stream",
-                "uri",
-                "url"
-            ],
-            "time": "2018-12-04T20:46:45+00:00"
-        },
-        {
-            "name": "lullabot/amp",
-            "version": "dev-amphtml-generator",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/dennisinteractive/amp-library.git",
-                "reference": "9d43a701a5ac7773bbc3f74976b0ed176631c7e7"
-            },
-            "dist": {
-                "type": "zip",
-                "url": "https://api.github.com/repos/dennisinteractive/amp-library/zipball/9d43a701a5ac7773bbc3f74976b0ed176631c7e7",
-                "reference": "9d43a701a5ac7773bbc3f74976b0ed176631c7e7",
-                "shasum": ""
-            },
-            "require": {
-                "guzzlehttp/guzzle": "~6.1",
-                "marc1706/fast-image-size": "1.*",
-                "masterminds/html5": "~2.0",
-                "php": ">=5.5.0",
-                "querypath/querypath": ">=3.0.4",
-                "sabberworm/php-css-parser": "^8.0.0",
-                "sebastian/diff": "^1.2 || ^2 || ^3"
-            },
-            "require-dev": {
-                "php": ">=5.5.0",
-                "phpunit/phpunit": "4.8.* || ^6",
-                "symfony/console": "^2.7.0"
-            },
-            "bin": [
-                "bin/amp-console"
-            ],
-            "type": "library",
-            "autoload": {
-                "classmap": [
-                    "src/Spec"
-                ],
-                "psr-4": {
-                    "Lullabot\\AMP\\": "src"
-                }
-            },
-            "license": [
-                "Apache-2.0"
-            ],
-            "authors": [
-                {
-                    "name": "Sidharth Kshatriya",
-                    "email": "sid.kshatriya@gmail.com"
-                }
-            ],
-            "description": "A set of useful classes and utilities to convert html to AMP html (See https://www.ampproject.org/)",
-            "homepage": "https://github.com/Lullabot/amp-library",
-            "keywords": [
-                "AMP",
-                "Drupal",
-                "mobile"
-            ],
-            "support": {
-                "source": "https://github.com/dennisinteractive/amp-library/tree/amphtml-generator"
-            },
-            "time": "2018-12-07T08:53:09+00:00"
-        },
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-                "php": ">=5.3.0"
-            },
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-                "phpunit/phpunit": "4.*"
-            },
-            "type": "library",
-            "autoload": {
-                "psr-4": {
-                    "FastImageSize\\": "lib",
-                    "FastImageSize\\tests\\": "tests"
-                }
-            },
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "MIT"
-            ],
-            "authors": [
-                {
-                    "name": "Marc Alexander",
-                    "email": "admin@m-a-styles.de",
-                    "homepage": "https://www.m-a-styles.de",
-                    "role": "Developer"
-                }
-            ],
-            "description": "fast-image-size is a PHP library that does almost everything PHP's getimagesize() does but without the large overhead of downloading the complete file.",
-            "homepage": "https://www.m-a-styles.de",
-            "keywords": [
-                "fast",
-                "getimagesize",
-                "image",
-                "imagesize",
-                "php",
-                "size"
-            ],
-            "time": "2017-10-23T18:52:01+00:00"
-        },
-        {
-            "name": "masterminds/html5",
-            "version": "2.4.0",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/Masterminds/html5-php.git",
-                "reference": "cadcfaaa13153e0e8eb92c49a53e140cf1a85dea"
-            },
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