[DevTools] Make resource tree model optional

third_party/WebKit/Source/devtools/front_end/elements/ElementsSidebarPane.js

 // Copyright (c) 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
  * @extends {WebInspector.SidebarPane}
  * @param {string} title
  */
 WebInspector.ElementsSidebarPane = function(title)
@@ skipping 70 matching lines @@
             WebInspector.EventTarget.removeEventListeners(this._targetEvents);
             this._targetEvents = null;
         }
         this._target = target;
 
         var domModel = null;
         var resourceTreeModel = null;
         if (target) {
             this._cssModel = WebInspector.CSSModel.fromTarget(target);
             domModel = WebInspector.DOMModel.fromTarget(target);
-            resourceTreeModel = target.resourceTreeModel;
+            resourceTreeModel = WebInspector.ResourceTreeModel.fromTarget(target);
         }
 
         if (this._cssModel && domModel && resourceTreeModel) {

[dgozman, 2016/07/14 16:29:28]

We should split "&& resourceTreeModel" out. This pane can function without
resourceTreeModel.

[eostroukhov-old, 2016/07/20 23:46:15]

This code have been removed.

             this._targetEvents = [
                 this._cssModel.addEventListener(WebInspector.CSSModel.Events.StyleSheetAdded, this.onCSSModelChanged, this),
                 this._cssModel.addEventListener(WebInspector.CSSModel.Events.StyleSheetRemoved, this.onCSSModelChanged, this),
                 this._cssModel.addEventListener(WebInspector.CSSModel.Events.StyleSheetChanged, this.onCSSModelChanged, this),
                 this._cssModel.addEventListener(WebInspector.CSSModel.Events.MediaQueryResultChanged, this.onCSSModelChanged, this),
                 this._cssModel.addEventListener(WebInspector.CSSModel.Events.PseudoStateForced, this.onCSSModelChanged, this),
                 this._cssModel.addEventListener(WebInspector.CSSModel.Events.ModelWasEnabled, this.onCSSModelChanged, this),
                 domModel.addEventListener(WebInspector.DOMModel.Events.DOMMutated, this._domModelChanged, this),
                 resourceTreeModel.addEventListener(WebInspector.ResourceTreeModel.EventTypes.FrameResized, this._onFrameResized, this),
             ];
@@ skipping 74 matching lines @@
             return this._view.isShowing() ? this._doUpdate.call(null) : Promise.resolve();
         }
     },
 
     viewWasShown: function()
     {
         if (this._updateWhenVisible)
             this.update();
     }
 }