Impl thread smooth scrolling.

cc/animation/layer_animation_controller.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_ANIMATION_LAYER_ANIMATION_CONTROLLER_H_
 #define CC_ANIMATION_LAYER_ANIMATION_CONTROLLER_H_
 
 #include "base/basictypes.h"
 #include "base/containers/hash_tables.h"
 #include "base/memory/ref_counted.h"
@@ skipping 94 matching lines @@
 
   void remove_value_provider(LayerAnimationValueProvider* provider) {
     if (value_provider_ == provider)
       value_provider_ = NULL;
   }
 
   void set_layer_animation_delegate(AnimationDelegate* delegate) {
     layer_animation_delegate_ = delegate;
   }
 
+  void remove_layer_animation_delegate(AnimationDelegate* delegate) {
+    if (layer_animation_delegate_ == delegate)
+      layer_animation_delegate_ = NULL;
+  }
+
   bool HasFilterAnimationThatInflatesBounds() const;
   bool HasTransformAnimationThatInflatesBounds() const;
   bool HasAnimationThatInflatesBounds() const {
     return HasTransformAnimationThatInflatesBounds() ||
            HasFilterAnimationThatInflatesBounds();
   }
 
   bool FilterAnimationBoundsForBox(const gfx::BoxF& box,
                                    gfx::BoxF* bounds) const;
   bool TransformAnimationBoundsForBox(const gfx::BoxF& box,
@@ skipping 80 matching lines @@
   // Only try to start animations when new animations are added or when the
   // previous attempt at starting animations failed to start all animations.
   bool needs_to_start_animations_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerAnimationController);
 };
 
 }  // namespace cc
 
 #endif  // CC_ANIMATION_LAYER_ANIMATION_CONTROLLER_H_