DevTools: move emulation button into the base App.js.

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()
 {
+    if (WebInspector.overridesSupport.canEmulate()) {
+        this._toggleEmulationButton = new WebInspector.StatusBarButton(WebInspector.UIString("Toggle emulation enabled."), "emulation-status-bar-item");
+        this._toggleEmulationButton.toggled = WebInspector.overridesSupport.emulationEnabled();
+        this._toggleEmulationButton.addEventListener("click", this._toggleEmulationEnabled, this);
+        WebInspector.overridesSupport.addEventListener(WebInspector.OverridesSupport.Events.EmulationStateChanged, this._emulationEnabledChanged, this);
+    }
 };
 
 WebInspector.App.prototype = {
+    _toggleEmulationEnabled: function()
+    {
+        WebInspector.overridesSupport.setEmulationEnabled(!this._toggleEmulationButton.toggled);
+    },
+
+    _emulationEnabledChanged: function()
+    {
+        this._toggleEmulationButton.toggled = WebInspector.overridesSupport.emulationEnabled();
+        if (!WebInspector.overridesSupport.responsiveDesignAvailable() && WebInspector.overridesSupport.emulationEnabled())
+            WebInspector.inspectorView.showViewInDrawer("emulation", true);
+    },
+
     createRootView: function()
     {
     },
 
     presentUI: function()
     {
         WebInspector.inspectorView.showInitialPanel();
 
         WebInspector.overridesSupport.applyInitialOverrides();
-        if (WebInspector.overridesSupport.hasActiveOverrides() && !WebInspector.experimentsSettings.responsiveDesign.isEnabled())
+        if (!WebInspector.overridesSupport.responsiveDesignAvailable() && WebInspector.overridesSupport.emulationEnabled())
             WebInspector.inspectorView.showViewInDrawer("emulation", true);
     }
 };
 
 /**
+ * @constructor
+ * @implements {WebInspector.StatusBarButton.Provider}
+ */
+WebInspector.App.EmulationButtonProvider = function()
+{
+}
+
+WebInspector.App.EmulationButtonProvider.prototype = {
+    /**
+     * @return {?WebInspector.StatusBarButton}
+     */
+    button: function()
+    {
+        if (!(WebInspector.app instanceof WebInspector.App))
+            return null;
+        return WebInspector.app._toggleEmulationButton || null;
+    }
+}
+
+/**
  * @type {!WebInspector.App}
  */
 WebInspector.app;