Fix compile error on clang

ash/desktop_background/desktop_background_widget_controller.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_WIDGET_CONTROLLER_H_
 #define ASH_DESKTOP_BACKGROUND_DESKTOP_BACKGROUND_WIDGET_CONTROLLER_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "ui/aura/window_property.h"
 #include "ui/compositor/layer.h"
@@ skipping 39 matching lines @@
 
 // This class wraps a DesktopBackgroundWidgetController pointer. It is installed
 // as an owned property on the RootWindow. DesktopBackgroundWidgetController is
 // moved to this property before animation completes. After animation completes,
 // the kWindowDesktopComponent property on RootWindow is set to the
 // DesktopBackgroundWidgetController in this class.
 class ComponentWrapper {
  public:
   explicit ComponentWrapper(
       DesktopBackgroundWidgetController* component);
-  ~ComponentWrapper() {}
+  ~ComponentWrapper();
 
   // Gets the wrapped DesktopBackgroundWidgetController pointer. Caller should
   // take ownership of the pointer if |pass_ownership| is true.
   DesktopBackgroundWidgetController* GetComponent(bool pass_ownership);
 
  private:
   scoped_ptr<DesktopBackgroundWidgetController> component_;
 
   DISALLOW_COPY_AND_ASSIGN(ComponentWrapper);
 };
 
 // Window property key, that binds instance of DesktopBackgroundWidgetController
 // to root windows.
 extern const aura::WindowProperty<DesktopBackgroundWidgetController*>* const
     kWindowDesktopComponent;
 
 extern const aura::WindowProperty<ComponentWrapper*>* const kComponentWrapper;
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_DESKTOP_BACKGROUND_DESKTOP_BACKGROUND_WIDGET_CONTROLLER_H_