Replace more ObserverList with base::ObserverList.

components/wallpaper/wallpaper_manager_base.h

 // Copyright 2014 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 COMPONENTS_WALLPAPER_WALLPAPER_MANAGER_BASE_H_
 #define COMPONENTS_WALLPAPER_WALLPAPER_MANAGER_BASE_H_
 
 #include <deque>
 #include <map>
 #include <string>
@@ skipping 571 matching lines @@
   // Caches wallpapers of users. Accessed only on UI thread.
   CustomWallpaperMap wallpaper_cache_;
 
   // The last selected user on user pod row.
   std::string last_selected_user_;
 
   bool should_cache_wallpaper_;
 
   content::NotificationRegistrar registrar_;
 
-  ObserverList<Observer> observers_;
+  base::ObserverList<Observer> observers_;
 
   // These members are for the scheduler:
 
   // When last load attempt finished.
   base::Time last_load_finished_at_;
 
   // last N wallpaper loads times.
   std::deque<base::TimeDelta> last_load_times_;
 
   base::FilePath default_small_wallpaper_file_;
@@ skipping 10 matching lines @@
 
   base::WeakPtrFactory<WallpaperManagerBase> weak_factory_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(WallpaperManagerBase);
 };
 
 }  // namespace chromeos
 
 #endif  // COMPONENTS_WALLPAPER_WALLPAPER_MANAGER_BASE_H_