Make GetRootWindow() return a Window instead of a RootWindow.

ash/root_window_controller.h

 // Copyright (c) 2012 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.
 
 #ifndef ASH_ROOT_WINDOW_CONTROLLER_H_
 #define ASH_ROOT_WINDOW_CONTROLLER_H_
 
 #include <map>
 
 #include "ash/ash_export.h"
@@ skipping 184 matching lines @@
   // Deletes associated objects and clears the state, but doesn't delete
   // the root window yet. This is used to delete a secondary displays'
   // root window safely when the display disconnect signal is received,
   // which may come while we're in the nested message loop.
   void Shutdown();
 
   // Deletes all child windows and performs necessary cleanup.
   void CloseChildWindows();
 
   // Moves child windows to |dest|.
-  void MoveWindowsTo(aura::RootWindow* dest);
+  void MoveWindowsTo(aura::Window* dest);
 
   // Force the shelf to query for it's current visibility state.
   void UpdateShelfVisibility();
 
   // Initialize touch HUDs if necessary.
   void InitTouchHuds();
 
   // Returns the window, if any, which is in fullscreen mode. If multiple
   // windows are in fullscreen state, the topmost one is preferred.
   const aura::Window* GetTopmostFullscreenWindow() const;
@@ skipping 78 matching lines @@
   scoped_ptr<DesktopBackgroundWidgetController> wallpaper_controller_;
   scoped_ptr<AnimatingDesktopController> animating_wallpaper_controller_;
   scoped_ptr<views::corewm::ScopedCaptureClient> capture_client_;
 
   DISALLOW_COPY_AND_ASSIGN(RootWindowController);
 };
 
 
 // Gets the RootWindowController for |root_window|.
 ASH_EXPORT RootWindowController* GetRootWindowController(
-    const aura::RootWindow* root_window);
+    const aura::Window* root_window);
 
 }  // namespace internal
 }  // ash
 
 #endif  //  ASH_ROOT_WINDOW_CONTROLLER_H_