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

ash/wm/overview/window_selector_panels.h

 // 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.
 
 #ifndef ASH_WM_OVERVIEW_WINDOW_SELECTOR_PANELS_H_
 #define ASH_WM_OVERVIEW_WINDOW_SELECTOR_PANELS_H_
 
 #include "ash/wm/overview/window_selector_item.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_vector.h"
 #include "ui/gfx/rect.h"
 
-namespace aura {
-class RootWindow;
-class Window;
-}
-
 namespace ash {
 
 class ScopedTransformOverviewWindow;
 
 // This class implements a window selector item containing one or more attached
 // panel windows. These panels are grouped into a single overview item in
 // overview mode and the callout arrows are hidden at this point.
 class WindowSelectorPanels : public WindowSelectorItem {
  public:
   WindowSelectorPanels();
   virtual ~WindowSelectorPanels();
 
   // Adds |window| to the selector item. This window should be an attached
   // panel window.
   void AddWindow(aura::Window* window);
 
   // WindowSelectorItem:
-  virtual aura::RootWindow* GetRootWindow() OVERRIDE;
+  virtual aura::Window* GetRootWindow() OVERRIDE;
   virtual aura::Window* TargetedWindow(const aura::Window* target) OVERRIDE;
   virtual void RestoreWindowOnExit(aura::Window* window) OVERRIDE;
   virtual aura::Window* SelectionWindow() OVERRIDE;
   virtual void RemoveWindow(const aura::Window* window) OVERRIDE;
   virtual bool empty() const OVERRIDE;
   virtual void PrepareForOverview() OVERRIDE;
-  virtual void SetItemBounds(aura::RootWindow* root_window,
+  virtual void SetItemBounds(aura::Window* root_window,
                              const gfx::Rect& target_bounds,
                              bool animate) OVERRIDE;
 
  private:
   typedef ScopedVector<ScopedTransformOverviewWindow> WindowList;
   WindowList transform_windows_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowSelectorPanels);
 };
 
 }  // namespace ash
 
 #endif  // ASH_WM_OVERVIEW_WINDOW_SELECTOR_PANELS_H_