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

ash/wm/dock/docked_window_layout_manager.h

 // Copyright (c) 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_DOCK_DOCKED_WINDOW_LAYOUT_MANAGER_H_
 #define ASH_WM_DOCK_DOCKED_WINDOW_LAYOUT_MANAGER_H_
 
 #include "ash/ash_export.h"
 #include "ash/shelf/shelf_layout_manager_observer.h"
 #include "ash/shell_observer.h"
@@ skipping 125 matching lines @@
   virtual void OnWillRemoveWindowFromLayout(aura::Window* child) OVERRIDE {}
   virtual void OnWindowRemovedFromLayout(aura::Window* child) OVERRIDE;
   virtual void OnChildWindowVisibilityChanged(aura::Window* child,
                                               bool visibile) OVERRIDE;
   virtual void SetChildBounds(aura::Window* child,
                               const gfx::Rect& requested_bounds) OVERRIDE;
 
   // ash::ShellObserver:
   virtual void OnDisplayWorkAreaInsetsChanged() OVERRIDE;
   virtual void OnFullscreenStateChanged(bool is_fullscreen,
-                                        aura::RootWindow* root_window) OVERRIDE;
-  virtual void OnShelfAlignmentChanged(aura::RootWindow* root_window) OVERRIDE;
+                                        aura::Window* root_window) OVERRIDE;
+  virtual void OnShelfAlignmentChanged(aura::Window* root_window) OVERRIDE;
 
   // wm::WindowStateObserver:
   virtual void OnWindowShowTypeChanged(wm::WindowState* window_state,
                                        wm::WindowShowType old_type) OVERRIDE;
 
   // aura::WindowObserver:
   virtual void OnWindowBoundsChanged(aura::Window* window,
                                      const gfx::Rect& old_bounds,
                                      const gfx::Rect& new_bounds) OVERRIDE;
   virtual void OnWindowVisibilityChanging(aura::Window* window,
@@ skipping 115 matching lines @@
   // Observers of dock bounds changes.
   ObserverList<DockedWindowLayoutManagerObserver> observer_list_;
 
   DISALLOW_COPY_AND_ASSIGN(DockedWindowLayoutManager);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_WM_DOCK_DOCKED_WINDOW_LAYOUT_MANAGER_H_