Rename ash desktop_background to wallpaper.

ash/wallpaper/wallpaper_controller_observer.h

 // 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.
 
-#ifndef ASH_DESKTOP_BACKGROUND_DESKTOP_BACKGROUND_CONTROLLER_OBSERVER_H_
-#define ASH_DESKTOP_BACKGROUND_DESKTOP_BACKGROUND_CONTROLLER_OBSERVER_H_
+#ifndef ASH_WALLPAPER_WALLPAPER_CONTROLLER_OBSERVER_H_
+#define ASH_WALLPAPER_WALLPAPER_CONTROLLER_OBSERVER_H_
 
 #include "ash/ash_export.h"
 
 namespace ash {
 
-class ASH_EXPORT DesktopBackgroundControllerObserver {
+class ASH_EXPORT WallpaperControllerObserver {
  public:
   // Invoked when the wallpaper data is changed.
   virtual void OnWallpaperDataChanged() = 0;
 
  protected:
-  virtual ~DesktopBackgroundControllerObserver() {}
+  virtual ~WallpaperControllerObserver() {}
 };
 
 }  // namespace ash
 
-#endif  // ASH_DESKTOP_BACKGROUND_DESKTOP_BACKGROUND_CONTROLLER_OBSERVER_H_
+#endif  // ASH_WALLPAPER_WALLPAPER_CONTROLLER_OBSERVER_H_