[DevTools] Add Toolbox page to undocked DevTools frontend.

Source/devtools/front_end/main/App.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
  */
 WebInspector.App = function()
 {
 };
 
 WebInspector.App.prototype = {
     createRootView: function()
     {
     },
 
     createGlobalStatusBarItems: function()
     {
     },
 
     presentUI: function()
     {
         WebInspector.inspectorView.showInitialPanel();
 
         WebInspector.overridesSupport.applyInitialOverrides();
-        if (WebInspector.overridesSupport.hasActiveOverrides())
+        if (WebInspector.overridesSupport.hasActiveOverrides() && !WebInspector.experimentsSettings.responsiveDesign.isEnabled())
             WebInspector.inspectorView.showViewInDrawer("emulation", true);
     },
 
     appendInspectStatusBarItem: function()
     {
         if (WebInspector.inspectElementModeController)
             WebInspector.inspectorView.appendToLeftToolbar(WebInspector.inspectElementModeController.toggleSearchButton.element);
     },
 
     appendSettingsStatusBarItem: function()
     {
         WebInspector.inspectorView.appendToRightToolbar(WebInspector.settingsController.statusBarItem);
     }
 };
 
 /**
  * @type {!WebInspector.App}
  */
 WebInspector.app;