Open immersive experiences directly

This PR implements support for opening immersive experiences directly
as soon as the application is launched.

We do this by adding a built-in extension which will activate a
particular element in the page.

We need to set the preference dom.vr.require-gesture to false so this
script can launch immersive WebXR experiences.

The information required to identify the element to activate is passed
as parameters to the Intent:

- open_in_immersive
- open_in_immersive_parent_xpath
- open_in_immersive_element_xpath
- a target URL to open

app/src/common/shared/com/igalia/wolvic/VRBrowserActivity.java

@@ -127,6 +127,10 @@ public class VRBrowserActivity extends PlatformActivity implements WidgetManager
     public static final String EXTRA_HIDE_WHATS_NEW = "hide_whats_new";
     public static final String EXTRA_KIOSK = "kiosk";
     private static final long BATTERY_UPDATE_INTERVAL = 60 * 1_000_000_000L; // 60 seconds
+    public static final String EXTRA_OPEN_IN_IMMERSIVE = "open_in_immersive";
+    // Element where a click would be simulated to launch the WebXR experience.
+    public static final String EXTRA_OPEN_IN_IMMERSIVE_PARENT_XPATH = "open_in_immersive_parent_xpath";
+    public static final String EXTRA_OPEN_IN_IMMERSIVE_ELEMENT_XPATH = "open_in_immersive_element_xpath";
 
     private BroadcastReceiver mCrashReceiver = new BroadcastReceiver() {
         @Override
@@ -247,6 +251,8 @@ public void run() {
     private int mLastBatteryLevel = -1;
     private PlatformActivityPlugin mPlatformPlugin;
     private int mLastMotionEventWidgetHandle;
+    private String mImmersiveParentElementXPath;
+    private String mImmersiveTargetElementXPath;
 
     private boolean callOnAudioManager(Consumer<AudioManager> fn) {
         if (mAudioManager == null) {
@@ -803,6 +809,7 @@ void loadFromIntent(final Intent intent) {
         boolean openInWindow = false;
         boolean openInBackground = false;
         boolean openInKioskMode = false;
+        boolean openInImmersive = false;
 
         Uri dataUri = intent.getData();
         Uri targetUri = null;
@@ -879,6 +886,14 @@ void loadFromIntent(final Intent intent) {
             }
 
             openInKioskMode = extras.getBoolean(EXTRA_KIOSK, false);
+
+            if (extras.getBoolean(EXTRA_OPEN_IN_IMMERSIVE)) {
+                mImmersiveParentElementXPath = extras.getString(EXTRA_OPEN_IN_IMMERSIVE_PARENT_XPATH);
+                mImmersiveTargetElementXPath = extras.getString(EXTRA_OPEN_IN_IMMERSIVE_ELEMENT_XPATH);
+
+                // Open in immersive requires specific information to be present
+                openInImmersive = targetUri != null && mImmersiveTargetElementXPath != null;
+            }
         }
 
         // If there is a target URI we open it
@@ -890,6 +905,8 @@ void loadFromIntent(final Intent intent) {
             if (openInKioskMode) {
                 // FIXME this might not work as expected if the app was already running
                 mWindows.openInKioskMode(targetUri.toString());
+            } if (openInImmersive) {
+                mWindows.openInImmersiveMode(targetUri, mImmersiveParentElementXPath, mImmersiveTargetElementXPath);
             } else {
                 if (openInWindow) {
                     location = Windows.OPEN_IN_NEW_WINDOW;

app/src/common/shared/com/igalia/wolvic/ui/widgets/Windows.java

@@ -4,6 +4,7 @@
 
 import android.content.Context;
 import android.content.SharedPreferences;
+import android.net.Uri;
 import android.util.Log;
 
 import androidx.annotation.IntDef;
@@ -68,6 +69,8 @@ public class Windows implements TrayListener, TopBarWidget.Delegate, TitleBarWid
 
     public static final int WHITE = 0xFFFFFFFF;
     public static final int GRAY = 0x555555FF;
+    public static final String PARENT_ELEMENT_XPATH_PARAMETER = "wolvic-autowebxr-parentElementXPath";
+    public static final String TARGET_ELEMENT_XPATH_PARAMETER = "wolvic-autowebxr-targetElementXPath";
 
     @IntDef(value = { OPEN_IN_FOREGROUND, OPEN_IN_BACKGROUND, OPEN_IN_NEW_WINDOW})
     public @interface NewTabLocation {}
@@ -1470,6 +1473,32 @@ public void openInKioskMode(@NonNull String aUri) {
         mFocusedWindow.setKioskMode(true);
     }
 
+    public void openInImmersiveMode(Uri targetUri, String immersiveParentElementXPath, String immersiveTargetElementXPath) {
+        String extensionId = "[email protected]";
+        String extensionUrl = "resource://android/assets/extensions/wolvic_autowebxr/";
+
+        Uri.Builder uriBuilder = targetUri.buildUpon();
+        uriBuilder.appendQueryParameter(PARENT_ELEMENT_XPATH_PARAMETER, immersiveParentElementXPath);
+        uriBuilder.appendQueryParameter(TARGET_ELEMENT_XPATH_PARAMETER, immersiveTargetElementXPath);
+        Uri extendedUri = uriBuilder.build();
+
+        Session session = SessionStore.get().createSuspendedSession(extendedUri.toString(), true);
+
+        SessionStore.get().getWebExtensionRuntime().installWebExtension(
+                extensionId,
+                extensionUrl,
+                webExtension -> {
+                    setFirstPaint(mFocusedWindow, session);
+                    mFocusedWindow.setSession(session, WindowWidget.DEACTIVATE_CURRENT_SESSION);
+                    return null;
+                },
+                (s, throwable) -> {
+                    Log.e(LOGTAG, "Error installing the " + extensionId + " Web Extension: " + throwable.getLocalizedMessage());
+                    return null;
+                }
+        );
+    }
+
     public void addTab(@NonNull WindowWidget targetWindow, @Nullable String aUri) {
         Session session = SessionStore.get().createSuspendedSession(aUri, targetWindow.getSession().isPrivateMode());
         session.setParentSession(targetWindow.getSession());

app/src/main/assets/extensions/wolvic_autowebxr/content.js

@@ -0,0 +1,81 @@
+const LOGTAG = '[wolvic:autowebxr]';
+const ENABLE_LOGS = true;
+const logDebug = (...args) => ENABLE_LOGS && console.log(LOGTAG, ...args);
+
+const PARENT_ELEMENT_XPATH_PARAMETER = 'wolvic-autowebxr-parentElementXPath';
+const TARGET_ELEMENT_XPATH_PARAMETER = 'wolvic-autowebxr-targetElementXPath';
+
+var parentElementXPath;
+var targetElementXPath;
+
+function getElementByXPath(document, xpath) {
+    let result = document.evaluate(xpath, document, null, XPathResult.FIRST_ORDERED_NODE_TYPE, null);
+    return result.singleNodeValue;
+}
+
+function clickImmersiveElement() {
+    // check if the current URL has extra query parameters
+    parentElementXPath = undefined;
+    targetElementXPath = undefined;
+
+    let url = document.URL;
+    let params = new URLSearchParams(new URL(url).search);
+    for (let [key, value] of params) {
+        if (key === 'wolvic-autowebxr-parentElementXPath')
+            parentElementXPath = value
+        else if (key === 'wolvic-autowebxr-targetElementXPath')
+            targetElementXPath = value;
+    }
+
+    // we need at least the target element to click
+    if (!targetElementXPath)
+        return;
+
+    logDebug('Preparing to open immersive WebXR; parentElementXPath: ' + parentElementXPath + ' ; targetElementXPath: ' + targetElementXPath);
+
+    // the parent element is usually an iframe; if parentElementXPath is null, we use the root
+
+    var parent, parentDocument;
+    if (parentElementXPath) {
+        var parent = getElementByXPath(document, parentElementXPath);
+        if (!parent) {
+            logDebug('parent not found, retrying');
+            setTimeout(clickImmersiveElement, 1000);
+            return;
+        }
+        parentDocument = parent.contentDocument || parent.contentWindow.document;
+    } else {
+        parent = window;
+        parentDocument = document;
+    }
+
+    if (parentDocument.readyState !== 'complete') {
+        logDebug('parent is still loading');
+        parent.addEventListener('load', function() {
+            logDebug('parent has finished loading');
+            clickImmersiveElement();
+        });
+        return;
+    }
+
+    logDebug('parent is loaded');
+
+    let targetElement = getElementByXPath(parentDocument, targetElementXPath);
+
+    if (targetElement) {
+        logDebug('target element found, clicking');
+        // This fails with "DOMException: A user gesture is required" unless dom.vr.require-gesture is set to false.
+        targetElement.click();
+    } else {
+        logDebug('target element not found, retrying');
+        setTimeout(clickImmersiveElement, 1000);
+    }
+}
+
+if (document.readyState === 'complete') {
+    logDebug('document is completely ready');
+    clickImmersiveElement();
+} else {
+    logDebug('document is not ready yet');
+    window.addEventListener('load', clickImmersiveElement);
+}

app/src/main/assets/extensions/wolvic_autowebxr/manifest.json

@@ -0,0 +1,23 @@
+{
+  "manifest_version": 2,
+  "name": "Wolvic WebXR Automator",
+  "version": "1.0",
+  "description": "Enter WebXR Experiences Automatically",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "[email protected]"
+    }
+  },
+  "content_scripts": [
+    {
+      "matches": [
+        "*://*/*"
+      ],
+      "js": [
+        "content.js"
+      ],
+      "run_at": "document_idle",
+      "all_frames": false
+    }
+  ]
+}

app/src/main/res/raw/fxr_config.yaml

@@ -26,4 +26,6 @@ prefs:
   browser.gesture.pinch.in: ''
   browser.gesture.pinch.out.shift: ''
   browser.gesture.pinch.in.shift: ''
-  apz.one_touch_pinch.enabled: false
+  apz.one_touch_pinch.enabled: false,
+  # allows scripts to open WebXR immersive sessions
+  dom.vr.require-gesture: false