cc: Cleanup class/struct forward declarations

cc/test/animation_test_common.h

 // 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_TEST_ANIMATION_TEST_COMMON_H_
 #define CC_TEST_ANIMATION_TEST_COMMON_H_
 
 #include "cc/animation/animation.h"
 #include "cc/animation/animation_curve.h"
 #include "cc/animation/animation_timeline.h"
 #include "cc/animation/transform_operations.h"
 #include "cc/output/filter_operations.h"
 #include "cc/test/geometry_test_utils.h"
 #include "cc/trees/element_id.h"
 
 namespace cc {
 class AnimationPlayer;
-class LayerImpl;
-class Layer;
 }
 
 namespace gfx {
 class ScrollOffset;
 }
 
 namespace cc {
 
 class FakeFloatAnimationCurve : public FloatAnimationCurve {
  public:
@@ skipping 122 matching lines @@
     ElementId element_id,
     scoped_refptr<AnimationTimeline> timeline,
     double duration,
     float start_opacity,
     float end_opacity,
     bool use_timing_function);
 
 }  // namespace cc
 
 #endif  // CC_TEST_ANIMATION_TEST_COMMON_H_