[DevTools] Make resource tree model optional

third_party/WebKit/Source/devtools/front_end/screencast/ScreencastApp.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @constructor
  * @implements {WebInspector.App}
  * @implements {WebInspector.TargetManager.Observer}
  */
 WebInspector.ScreencastApp = function()
@@ skipping 28 matching lines @@
     /**
      * @override
      * @param {!WebInspector.Target} target
      */
     targetAdded: function(target)
     {
         if (this._target)
             return;
         this._target = target;
 
-        if (target.hasBrowserCapability()) {
-            this._screencastView = new WebInspector.ScreencastView(target);
+        var resourceTreeModel = WebInspector.ResourceTreeModel.fromTarget(target);
+        if (resourceTreeModel) {
+            this._screencastView = new WebInspector.ScreencastView(target, resourceTreeModel);
             this._rootSplitWidget.setMainWidget(this._screencastView);
             this._screencastView.initialize();
         } else {
             this._toggleButton.setEnabled(false);
         }
         this._onScreencastEnabledChanged();
     },
 
     /**
      * @override
@@ skipping 76 matching lines @@
 WebInspector.ScreencastAppProvider.prototype = {
     /**
      * @override
      * @return {!WebInspector.App}
      */
     createApp: function()
     {
         return WebInspector.ScreencastApp._instance();
     }
 };