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

ash/wm/lock_state_controller_unittest.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/wm/lock_state_controller.h"
 
 #include "ash/ash_switches.h"
 #include "ash/session_state_delegate.h"
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
@@ skipping 28 matching lines @@
 bool cursor_visible() {
   return ash::Shell::GetInstance()->cursor_manager()->IsCursorVisible();
 }
 
 void CheckCalledCallback(bool* flag) {
   if (flag)
     (*flag) = true;
 }
 
 aura::Window* GetContainer(int container ) {
-  aura::RootWindow* root_window = Shell::GetPrimaryRootWindow();
+  aura::Window* root_window = Shell::GetPrimaryRootWindow();
   return Shell::GetContainer(root_window, container);
 }
 
 bool IsBackgroundHidden() {
   return !GetContainer(internal::kShellWindowId_DesktopBackgroundContainer)->
               IsVisible();
 }
 
 void ShowBackground() {
   ui::ScopedLayerAnimationSettings settings(
@@ skipping 995 matching lines @@
 
   Advance(SessionStateAnimator::ANIMATION_SPEED_MOVE_WINDOWS);
   ExpectUnlockAfterUIDestroyedAnimationFinished();
   EXPECT_TRUE(IsBackgroundHidden());
 
   ExpectUnlockedState();
 }
 
 }  // namespace test
 }  // namespace ash