[DevTools] Refactor emulated devices modes.

Source/devtools/front_end/emulation/ResponsiveDesignView.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
  * @extends {WebInspector.VBox}
  * @implements {WebInspector.OverridesSupport.PageResizer}
  * @implements {WebInspector.TargetManager.Observer}
  * @param {!WebInspector.InspectedPagePlaceholder} inspectedPagePlaceholder
@@ skipping 716 matching lines @@
     },
 
     /**
      * @param {?WebInspector.EmulatedDevice} device
      * @param {?WebInspector.EmulatedDevice.Mode} mode
      */
     _deviceModeSelected: function(device, mode)
     {
         if (device && mode) {
             var orientation = device.orientationByName(mode.orientation);
-            this._deviceInsets = new Insets(mode.pageRect.left, mode.pageRect.top, orientation.width - mode.pageRect.left - mode.pageRect.width, orientation.height - mode.pageRect.top - mode.pageRect.height);
+            this._deviceInsets = mode.insets;
         } else {
             this._deviceInsets = new Insets(0, 0, 0, 0);
         }
         this.dispatchEventToListeners(WebInspector.OverridesSupport.PageResizer.Events.InsetsChanged, this._deviceInsets);
     },
 
     /**
      * @param {!EmulationAgent.Viewport=} viewport
      */
     _viewportChanged: function(viewport)
@@ skipping 75 matching lines @@
 WebInspector.EmulationDispatcher.prototype = {
     /**
      * @override
      * @param {!EmulationAgent.Viewport=} viewport
      */
     viewportChanged: function(viewport)
     {
         this._responsiveDesignView._viewportChanged(viewport);
     }
 }