Make aura::clients take Window instead of RootWindow

ui/aura/client/user_action_client.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 UI_AURA_CLIENT_USER_ACTION_CLIENT_H_
 #define UI_AURA_CLIENT_USER_ACTION_CLIENT_H_
 
 #include "ui/aura/aura_export.h"
 
 namespace aura {
-class RootWindow;
+class Window;
 namespace client {
 
 // An interface for handling a user action that isn't handled by the standard
 // event path.
 class AURA_EXPORT UserActionClient {
  public:
   enum Command {
     BACK = 0,
     FORWARD,
   };
 
   // Returns true if the command was handled and false otherwise.
   virtual bool OnUserAction(Command command) = 0;
 
   virtual ~UserActionClient() {}
 };
 
 // Sets/gets the client for handling user action on the specified root window.
-AURA_EXPORT void SetUserActionClient(RootWindow* root_window,
+AURA_EXPORT void SetUserActionClient(Window* root_window,
                                      UserActionClient* client);
-AURA_EXPORT UserActionClient* GetUserActionClient(RootWindow* root_window);
+AURA_EXPORT UserActionClient* GetUserActionClient(Window* root_window);
 
 }  // namespace client
 }  // namespace aura
 
 #endif  // UI_AURA_CLIENT_USER_ACTION_CLIENT_H_