CC Animations: Port Impl-only-scrolling to use compositor animation timelines.

cc/animation/animation_host.h

Index: cc/animation/animation_host.h
diff --git a/cc/animation/animation_host.h b/cc/animation/animation_host.h
index 2887ad8d8f8e767cee5a5c7efa125ca89e38d159..3f69a0233791de0cb138e657b45524c29b4f1b33 100644
--- a/cc/animation/animation_host.h
+++ b/cc/animation/animation_host.h
@@ -15,6 +15,10 @@
 #include "cc/base/cc_export.h"
 #include "cc/trees/mutator_host_client.h"
 
+namespace gfx {
+class ScrollOffset;
+}
+
 namespace cc {
 
 class AnimationPlayer;
@@ -120,6 +124,15 @@ class CC_EXPORT AnimationHost {
   bool HasAnyAnimation(int layer_id) const;
   bool HasActiveAnimation(int layer_id) const;
 
+  void ImplOnlyScrollAnimationCreate(int layer_id,
+                                     const gfx::ScrollOffset& target_offset,
+                                     const gfx::ScrollOffset& current_offset);
+  bool ImplOnlyScrollAnimationUpdateTarget(
+      int layer_id,
+      const gfx::Vector2dF& scroll_delta,
+      const gfx::ScrollOffset& max_scroll_offset,
+      base::TimeTicks frame_monotonic_time);
+
  private:
   explicit AnimationHost(ThreadInstance thread_instance);
 
@@ -141,6 +154,9 @@ class CC_EXPORT AnimationHost {
   scoped_ptr<AnimationRegistrar> animation_registrar_;
   MutatorHostClient* mutator_host_client_;
 
+  class ScrollOffsetAnimations;
+  scoped_ptr<ScrollOffsetAnimations> scroll_offset_animations_;
+
   const ThreadInstance thread_instance_;
 
   DISALLOW_COPY_AND_ASSIGN(AnimationHost);