DevTools: introduce screencast experiment.

Source/devtools/front_end/ResourceTreeModel.js

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 48 matching lines @@
     FrameDetached: "FrameDetached",
     MainFrameNavigated: "MainFrameNavigated",
     MainFrameCreatedOrNavigated: "MainFrameCreatedOrNavigated",
     ResourceAdded: "ResourceAdded",
     WillLoadCachedResources: "WillLoadCachedResources",
     CachedResourcesLoaded: "CachedResourcesLoaded",
     DOMContentLoaded: "DOMContentLoaded",
     Load: "Load",
     InspectedURLChanged: "InspectedURLChanged",
     SecurityOriginAdded: "SecurityOriginAdded",
-    SecurityOriginRemoved: "SecurityOriginRemoved"
+    SecurityOriginRemoved: "SecurityOriginRemoved",
+    ScreencastFrame: "ScreencastFrame",
 }
 
 WebInspector.ResourceTreeModel.prototype = {
     _fetchResourceTree: function()
     {
         /** @type {!Object.<string, !WebInspector.ResourceTreeFrame>} */
         this._frames = {};
         delete this._cachedResourcesProcessed;
         PageAgent.getResourceTree(this._processCachedResources.bind(this));
     },
@@ skipping 620 matching lines @@
     {
     },
 
     javascriptDialogClosed: function()
     {
     },
 
     scriptsEnabled: function(isEnabled)
     {
         WebInspector.settings.javaScriptDisabled.set(!isEnabled);
+    },
+
+    /**
+     * @param {string} data
+     */
+    screencastFrame: function(data)
+    {
+        this._resourceTreeModel.dispatchEventToListeners(WebInspector.ResourceTreeModel.EventTypes.ScreencastFrame, data);
     }
 }
 
 /**
  * @type {WebInspector.ResourceTreeModel}
  */
 WebInspector.resourceTreeModel = null;