Move GetRootWindowController() to root_window_controller.h

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 269 matching lines @@
   scoped_ptr<ToplevelWindowEventHandler> panel_container_handler_;
   scoped_ptr<ToplevelWindowEventHandler> docked_container_handler_;
 
   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);
+
 }  // namespace internal
 }  // ash
 
 #endif  //  ASH_ROOT_WINDOW_CONTROLLER_H_