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

ash/test/test_shell_delegate.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/test/test_shell_delegate.h"
 
 #include <limits>
 
 #include "ash/caps_lock_delegate_stub.h"
 #include "ash/default_accessibility_delegate.h"
@@ skipping 124 matching lines @@
 
 void TestShellDelegate::HandleMediaNextTrack() {
 }
 
 void TestShellDelegate::HandleMediaPlayPause() {
 }
 
 void TestShellDelegate::HandleMediaPrevTrack() {
 }
 
-ui::MenuModel* TestShellDelegate::CreateContextMenu(aura::RootWindow* root) {
+ui::MenuModel* TestShellDelegate::CreateContextMenu(aura::Window* root) {
   return NULL;
 }
 
 RootWindowHostFactory* TestShellDelegate::CreateRootWindowHostFactory() {
   // The ContextFactory must exist before any Compositors are created.
   bool allow_test_contexts = true;
   ui::Compositor::InitializeContextFactoryForTests(allow_test_contexts);
 
   return RootWindowHostFactory::Create();
 }
 
 base::string16 TestShellDelegate::GetProductName() const {
   return base::string16();
 }
 
 TestSessionStateDelegate* TestShellDelegate::test_session_state_delegate() {
   return test_session_state_delegate_;
 }
 
 }  // namespace test
 }  // namespace ash