ui: Cleanup class/struct forward declarations

ui/compositor/layer_animator.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 UI_COMPOSITOR_LAYER_ANIMATOR_H_
 #define UI_COMPOSITOR_LAYER_ANIMATOR_H_
 
 #include <deque>
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/linked_ptr.h"
 #include "base/memory/ref_counted.h"
 #include "base/observer_list.h"
 #include "base/time/time.h"
 #include "cc/animation/animation_delegate.h"
 #include "cc/animation/target_property.h"
 #include "ui/compositor/compositor_export.h"
 #include "ui/compositor/layer_animation_element.h"
 #include "ui/compositor/layer_threaded_animation_delegate.h"
 #include "ui/gfx/animation/tween.h"
 
 namespace cc {
 class Animation;
 class AnimationPlayer;
 class AnimationTimeline;
-class ElementAnimations;
 class Layer;
 }
 
 namespace gfx {
 class Animation;
 class Rect;
 class Transform;
 }
 
 namespace ui {
@@ skipping 365 matching lines @@
   // Observers are notified when layer animations end, are scheduled or are
   // aborted.
   base::ObserverList<LayerAnimationObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerAnimator);
 };
 
 }  // namespace ui
 
 #endif  // UI_COMPOSITOR_LAYER_ANIMATOR_H_