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

ash/focus_cycler_unittest.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/focus_cycler.h"
 
 #include "ash/launcher/launcher.h"
 #include "ash/root_window_controller.h"
 #include "ash/shelf/shelf_widget.h"
 #include "ash/shell.h"
@@ skipping 365 matching lines @@
   // Back to the shelf.
   focus_cycler()->RotateFocus(FocusCycler::BACKWARD);
   EXPECT_TRUE(shelf_widget()->IsActive());
 
   // Back to the status area.
   focus_cycler()->RotateFocus(FocusCycler::BACKWARD);
   EXPECT_TRUE(tray()->GetWidget()->IsActive());
 
   // Pressing "Escape" while on the status area should
   // deactivate it, and activate the browser window.
-  aura::RootWindow* root = Shell::GetPrimaryRootWindow();
+  aura::Window* root = Shell::GetPrimaryRootWindow();
   aura::test::EventGenerator event_generator(root, root);
   event_generator.PressKey(ui::VKEY_ESCAPE, 0);
   EXPECT_TRUE(wm::IsActiveWindow(browser_window));
   EXPECT_EQ(focus_manager->GetFocusedView(), view1);
 
   // Similarly, pressing "Escape" while on the shelf.
   // should do the same thing.
   focus_cycler()->RotateFocus(FocusCycler::BACKWARD);
   EXPECT_TRUE(shelf_widget()->IsActive());
   event_generator.PressKey(ui::VKEY_ESCAPE, 0);
   EXPECT_TRUE(wm::IsActiveWindow(browser_window));
   EXPECT_EQ(focus_manager->GetFocusedView(), view1);
 }
 
 }  // namespace test
 }  // namespace ash