Remove parts of //cc we aren't using

cc/animation/layer_animation_event_observer.h

Index: cc/animation/layer_animation_event_observer.h
diff --git a/cc/animation/layer_animation_event_observer.h b/cc/animation/layer_animation_event_observer.h
deleted file mode 100644
index 93d606edcc86553254fdcb769ae1addd2465bb80..0000000000000000000000000000000000000000
--- a/cc/animation/layer_animation_event_observer.h
+++ /dev/null
@@ -1,25 +0,0 @@
-// Copyright 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 CC_ANIMATION_LAYER_ANIMATION_EVENT_OBSERVER_H_
-#define CC_ANIMATION_LAYER_ANIMATION_EVENT_OBSERVER_H_
-
-#include "cc/base/cc_export.h"
-
-namespace cc {
-
-struct AnimationEvent;
-
-class CC_EXPORT LayerAnimationEventObserver {
- public:
-  virtual void OnAnimationStarted(const AnimationEvent& event) = 0;
-
- protected:
-  virtual ~LayerAnimationEventObserver() {}
-};
-
-}  // namespace cc
-
-#endif  // CC_ANIMATION_LAYER_ANIMATION_EVENT_OBSERVER_H_
-