Revert "chromeos: Move files in //ash/common to //ash, part 1"

ash/system/network/network_icon_animation_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_SYSTEM_NETWORK_NETWORK_ICON_ANIMATION_OBSERVER_H_
-#define ASH_SYSTEM_NETWORK_NETWORK_ICON_ANIMATION_OBSERVER_H_
-
-#include "ash/ash_export.h"
-
-namespace ash {
-namespace network_icon {
-
-// Observer interface class for animating network icons.
-class ASH_EXPORT AnimationObserver {
- public:
-  // Called when the image has changed due to animation. The callback should
-  // trigger a call to GetImageForNetwork() to retrieve the image.
-  virtual void NetworkIconChanged() = 0;
-
- protected:
-  virtual ~AnimationObserver() {}
-};
-
-}  // namespace network_icon
-}  // namespace ash
-
-#endif  // ASH_SYSTEM_NETWORK_NETWORK_ICON_ANIMATION_OBSERVER_H_