Introduce RootWindowProperty for RootWindow's properties

ash/wm/property_util.cc

 // 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.
 
 #include "ash/wm/property_util.h"
 
 #include "ash/ash_export.h"
+#include "ash/root_window_property.h"
 #include "ash/screen_ash.h"
 #include "ash/wm/window_properties.h"
 #include "ash/wm/window_util.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/root_window.h"
 #include "ui/aura/window.h"
 #include "ui/base/ui_base_types.h"
 #include "ui/gfx/rect.h"
 
 namespace ash {
@@ skipping 42 matching lines @@
   window->SetProperty(internal::kWindowRestoresToRestoreBounds, value);
 }
 
 bool GetWindowAlwaysRestoresToRestoreBounds(const aura::Window* window) {
   return window->GetProperty(internal::kWindowRestoresToRestoreBounds);
 }
 
 internal::RootWindowController* GetRootWindowController(
     const aura::RootWindow* root_window) {
   return root_window ?
-      root_window->GetProperty(internal::kRootWindowControllerKey) : NULL;
+      internal::GetRootWindowProperty(root_window)->controller : NULL;
 }
 
 void SetRootWindowController(aura::RootWindow* root_window,
                              internal::RootWindowController* controller) {
-  root_window->SetProperty(internal::kRootWindowControllerKey, controller);
+  internal::GetRootWindowProperty(root_window)->controller = controller;
 }
 
 }  // namespace ash