CC Animation: Merge LayerAnimationController into ElementAnimations.

cc/animation/layer_animation_value_provider.h

-// Copyright 2013 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_VALUE_PROVIDER_H_
-#define CC_ANIMATION_LAYER_ANIMATION_VALUE_PROVIDER_H_
-
-#include "cc/base/cc_export.h"
-
-namespace gfx {
-class ScrollOffset;
-}
-
-namespace cc {
-
-// A LayerAnimationValueProvider is used for determining the starting value
-// for animations that start at their 'current' value rather than at a
-// pre-specified value.
-class CC_EXPORT LayerAnimationValueProvider {
- public:
-  virtual ~LayerAnimationValueProvider() {}
-
-  virtual gfx::ScrollOffset ScrollOffsetForAnimation() const = 0;
-};
-
-}  // namespace cc
-
-#endif  // CC_ANIMATION_LAYER_ANIMATION_VALUE_PROVIDER_H_