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

ash/root_window_settings.cc

 // Copyright 2013 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/root_window_settings.h"
 
 #include "ui/aura/root_window.h"
 #include "ui/aura/window_property.h"
 #include "ui/gfx/display.h"
 
 DECLARE_WINDOW_PROPERTY_TYPE(ash::internal::RootWindowSettings*);
 
 namespace ash {
 namespace internal {
 
 DEFINE_OWNED_WINDOW_PROPERTY_KEY(RootWindowSettings,
                                  kRootWindowSettingsKey, NULL);
 
 RootWindowSettings::RootWindowSettings()
     : solo_window_header(false),
       display_id(gfx::Display::kInvalidDisplayID),
       controller(NULL) {
 }
 
-RootWindowSettings* InitRootWindowSettings(aura::RootWindow* root) {
+RootWindowSettings* InitRootWindowSettings(aura::Window* root) {
   RootWindowSettings* settings = new RootWindowSettings();
   root->SetProperty(kRootWindowSettingsKey, settings);
   return settings;
 }
 
-RootWindowSettings* GetRootWindowSettings(aura::RootWindow* root) {
+RootWindowSettings* GetRootWindowSettings(aura::Window* root) {
   return root->GetProperty(kRootWindowSettingsKey);
 }
 
-const RootWindowSettings* GetRootWindowSettings(const aura::RootWindow* root) {
+const RootWindowSettings* GetRootWindowSettings(const aura::Window* root) {
   return root->GetProperty(kRootWindowSettingsKey);
 }
 
 }  // namespace internal
 }  // namespace ash