Use ash NetworkIconAnimation in NetworkMenuIcon code

ash/system/chromeos/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_CHROMEOS_NETWORK_NETWORK_ICON_ANIMATION_OBSERVER_H_
 #define ASH_SYSTEM_CHROMEOS_NETWORK_NETWORK_ICON_ANIMATION_OBSERVER_H_
 
+#include "ash/ash_export.h"
+
 namespace ash {
 namespace network_icon {
 
 // Observer interface class for animating network icons.
-class AnimationObserver {
+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_CHROMEOS_NETWORK_NETWORK_ICON_ANIMATION_OBSERVER_H_