Add vertical 'divider' next to the 'Accept' and 'Reject' buttons

Per the designs, this applies the 'divider.'
There are about 20px on either side of it,
per a design decision to make this space similar
to that on /wp-admin/edit.php?post_type=page,
between 'Apply' and 'All dates.'

assets/css/amp-validation-single-error-url.css

@@ -140,3 +140,16 @@ table.striped > tbody > tr.even {
 #post-body-content button.reject {
 	margin-left: 4px;
 }
+
+#accept-reject-buttons:not(.hidden) {
+	display: inline-block;
+}
+
+#vertical-divider {
+	display: inline-block;
+	vertical-align: middle;
+	width: 15px;
+	margin-right: 15px;
+	height: 30px;
+	border-right: 1px solid #a0a5aa;
+}

assets/js/amp-invalid-url-post-edit-screen.js

@@ -307,6 +307,7 @@ var ampInvalidUrlPostEditScreen = ( function() { // eslint-disable-line no-unuse
 	component.handleBulkActions = function handleBulkActions() {
 		const acceptButton = document.querySelector( 'button.action.accept' );
 		const rejectButton = document.querySelector( 'button.action.reject' );
+		const acceptAndRejectContainer = document.getElementById( 'accept-reject-buttons' );
 
 		const onChange = function( event ) {
 			let areThereCheckedBoxes;
@@ -317,8 +318,7 @@ var ampInvalidUrlPostEditScreen = ( function() { // eslint-disable-line no-unuse
 
 			if ( event.target.checked ) {
 				// This checkbox was checked, so ensure the buttons display.
-				acceptButton.classList.remove( 'hidden' );
-				rejectButton.classList.remove( 'hidden' );
+				acceptAndRejectContainer.classList.remove( 'hidden' );
 			} else {
 				/*
 				 * This checkbox was unchecked.
@@ -332,8 +332,7 @@ var ampInvalidUrlPostEditScreen = ( function() { // eslint-disable-line no-unuse
 					}
 				} );
 				if ( ! areThereCheckedBoxes ) {
-					acceptButton.classList.add( 'hidden' );
-					rejectButton.classList.add( 'hidden' );
+					acceptAndRejectContainer.classList.add( 'hidden' );
 				}
 			}
 		};

includes/validation/class-amp-invalid-url-post-type.php

@@ -1753,8 +1753,11 @@ public static function render_single_url_list_table( $post ) {
 			<?php $wp_list_table->search_box( esc_html__( 'Search Errors', 'amp' ), 'invalid-url-search' ); ?>
 		</form>
 
-		<button type="button" class="hidden button action accept"><?php esc_html_e( 'Accept', 'amp' ); ?></button>
-		<button type="button" class="hidden button action reject"><?php esc_html_e( 'Reject', 'amp' ); ?></button>
+		<div id="accept-reject-buttons" class="hidden">
+			<button type="button" class="button action accept"><?php esc_html_e( 'Accept', 'amp' ); ?></button>
+			<button type="button" class="button action reject"><?php esc_html_e( 'Reject', 'amp' ); ?></button>
+			<div id="vertical-divider"></div>
+		</div>
 		<div id="url-post-filter" class="alignleft actions">
 			<?php AMP_Validation_Error_Taxonomy::render_error_type_filter(); ?>
 		</div>

tests/validation/test-class-amp-invalid-url-post-type.php

@@ -1237,8 +1237,9 @@ public function test_render_single_url_list_table() {
 		AMP_Invalid_URL_Post_Type::render_single_url_list_table( $post_correct_post_type );
 		$output = ob_get_clean();
 		$this->assertContains( '<form class="search-form wp-clearfix" method="get">', $output );
-		$this->assertContains( '<button type="button" class="hidden button action accept">', $output );
-		$this->assertContains( '<button type="button" class="hidden button action reject">', $output );
+		$this->assertContains( '<div id="accept-reject-buttons" class="hidden">', $output );
+		$this->assertContains( '<button type="button" class="button action accept">', $output );
+		$this->assertContains( '<button type="button" class="button action reject">', $output );
 	}
 
 	/**