app: Remove animation header files.

app/animation_delegate.h

-// Copyright (c) 2010 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 APP_ANIMATION_DELEGATE_H_
-#define APP_ANIMATION_DELEGATE_H_
-#pragma once
-
-class Animation;
-
-// AnimationDelegate
-//
-//  Implement this interface when you want to receive notifications about the
-//  state of an animation.
-class AnimationDelegate {
- public:
-  // Called when an animation has completed.
-  virtual void AnimationEnded(const Animation* animation) {}
-
-  // Called when an animation has progressed.
-  virtual void AnimationProgressed(const Animation* animation) {}
-
-  // Called when an animation has been canceled.
-  virtual void AnimationCanceled(const Animation* animation) {}
-
- protected:
-  virtual ~AnimationDelegate() {}
-};
-
-#endif  // APP_ANIMATION_DELEGATE_H_