Replace more ObserverList with base::ObserverList.

ash/wm/window_state.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_WINDOW_STATE_H_
 #define ASH_WM_WINDOW_STATE_H_
 
 #include "ash/ash_export.h"
 #include "ash/wm/drag_details.h"
 #include "ash/wm/wm_types.h"
@@ skipping 352 matching lines @@
   bool in_immersive_fullscreen_;
   bool hide_shelf_when_fullscreen_;
   bool minimum_visibility_;
   bool can_be_dragged_;
 
   // A property to remember the window position which was set before the
   // auto window position manager changed the window bounds, so that it can get
   // restored when only this one window gets shown.
   scoped_ptr<gfx::Rect> pre_auto_manage_window_bounds_;
 
-  ObserverList<WindowStateObserver> observer_list_;
+  base::ObserverList<WindowStateObserver> observer_list_;
 
   // True to ignore a property change event to avoid reentrance in
   // UpdateWindowStateType()
   bool ignore_property_change_;
 
   scoped_ptr<State> current_state_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowState);
 };
 
 // Returns the WindowState for active window. Returns |NULL|
 // if there is no active window.
 ASH_EXPORT WindowState* GetActiveWindowState();
 
 // Returns the WindowState for |window|. Creates WindowState
 // if it didn't exist. The settings object is owned by |window|.
 ASH_EXPORT WindowState* GetWindowState(aura::Window* window);
 
 // const version of GetWindowState.
 ASH_EXPORT const WindowState*
 GetWindowState(const aura::Window* window);
 
 }  // namespace wm
 }  // namespace ash
 
 #endif  // ASH_WM_WINDOW_STATE_H_