app: Remove animation header files.

app/animation_container_observer.h

Index: app/animation_container_observer.h
diff --git a/app/animation_container_observer.h b/app/animation_container_observer.h
deleted file mode 100644
index 9f74a91156a68a8cd8489c6e9d188d0f80dc54e3..0000000000000000000000000000000000000000
--- a/app/animation_container_observer.h
+++ /dev/null
@@ -1,27 +0,0 @@
-// 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_CONTAINER_OBSERVER_H_
-#define APP_ANIMATION_CONTAINER_OBSERVER_H_
-#pragma once
-
-class AnimationContainer;
-
-// The observer is notified after every update of the animations managed by
-// the container.
-class AnimationContainerObserver {
- public:
-  // Invoked on every tick of the timer managed by the container and after
-  // all the animations have updated.
-  virtual void AnimationContainerProgressed(
-      AnimationContainer* container) = 0;
-
-  // Invoked when no more animations are being managed by this container.
-  virtual void AnimationContainerEmpty(AnimationContainer* container) = 0;
-
- protected:
-  virtual ~AnimationContainerObserver() {}
-};
-
-#endif  // APP_ANIMATION_CONTAINER_OBSERVER_H_