browser(firefox): basic screencast implementation for GTK (#2818)

Author: yury-s

browser_patches/firefox/BUILD_NUMBER

@@ -1 +1 @@
-1118
+1119

browser_patches/firefox/juggler/moz.build

@@ -2,7 +2,7 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
-DIRS += ["components"]
+DIRS += ["components", "screencast"]
 
 JAR_MANIFESTS += ["jar.mn"]
 #JS_PREFERENCE_FILES += ["prefs/marionette.js"]

browser_patches/firefox/juggler/protocol/PageHandler.js

@@ -90,6 +90,7 @@ class PageHandler {
     this._dialogs = new Map();
 
     this._enabled = false;
+    this._videoSessionId = -1;
   }
 
   _onWorkerCreated({workerId, frameId, url}) {
@@ -284,6 +285,21 @@ class PageHandler {
       throw new Error('ERROR: cannot find worker with id ' + workerId);
     return await worker.sendMessage(JSON.parse(message));
   }
+
+  startVideoRecording({file, width, height, scale}) {
+    const screencast = Cc['@mozilla.org/juggler/screencast;1'].getService(Ci.nsIScreencastService);
+    const docShell = this._pageTarget._gBrowser.ownerGlobal.docShell;
+    this._videoSessionId = screencast.startVideoRecording(docShell, file);
+  }
+
+  stopVideoRecording() {
+    if (this._videoSessionId === -1)
+      throw new Error('No video recording in progress');
+    const videoSessionId = this._videoSessionId;
+    this._videoSessionId = -1;
+    const screencast = Cc['@mozilla.org/juggler/screencast;1'].getService(Ci.nsIScreencastService);
+    screencast.stopVideoRecording(videoSessionId);
+  }
 }
 
 class Dialog {

browser_patches/firefox/juggler/protocol/Protocol.js

@@ -825,6 +825,16 @@ const Page = {
         message: t.String,
       },
     },
+    'startVideoRecording': {
+      params: {
+        file: t.String,
+        width: t.Number,
+        height: t.Number,
+        scale: t.Optional(t.Number),
+      },
+    },
+    'stopVideoRecording': {
+    },
   },
 };