Unify Android Webview and Chrome's fling

cc/trees/layer_tree_host_impl.h

Index: cc/trees/layer_tree_host_impl.h
diff --git a/cc/trees/layer_tree_host_impl.h b/cc/trees/layer_tree_host_impl.h
index 54776e77315b74a08c74c23351547aeb77b6bc73..547e1ea91698986235ca7ee1e979cd8b5739764a 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -180,7 +180,7 @@ class CC_EXPORT LayerTreeHostImpl
                                bool anchor_point,
                                float page_scale,
                                base::TimeDelta duration);
-  void SetNeedsAnimate() override;
+  void SetNeedsAnimateInput() override;
   bool IsCurrentlyScrollingLayerAt(const gfx::Point& viewport_point,
                                    InputHandler::ScrollInputType type) override;
   bool HaveWheelEventHandlersAt(const gfx::Point& viewport_point) override;
@@ -385,6 +385,7 @@ class CC_EXPORT LayerTreeHostImpl
   bool AnimationsAreVisible() { return visible() && CanDraw(); }
 
   void SetNeedsCommit() { client_->SetNeedsCommitOnImplThread(); }
+  void SetNeedsAnimate();
   void SetNeedsRedraw();
 
   ManagedMemoryPolicy ActualManagedMemoryPolicy() const;
@@ -582,6 +583,7 @@ class CC_EXPORT LayerTreeHostImpl
   // outer if the inner is at its scroll extents.
   void ScrollViewportInnerFirst(gfx::Vector2dF scroll_delta);
 
+  void AnimateInput(base::TimeTicks monotonic_time);
   void AnimatePageScale(base::TimeTicks monotonic_time);
   void AnimateScrollbars(base::TimeTicks monotonic_time);
   void AnimateTopControls(base::TimeTicks monotonic_time);
@@ -680,6 +682,8 @@ class CC_EXPORT LayerTreeHostImpl
 
   // The optional delegate for the root layer scroll offset.
   LayerScrollOffsetDelegate* root_layer_scroll_offset_delegate_;
+  LayerScrollOffsetDelegate::AnimationCallback root_layer_animation_callback_;
+
   const LayerTreeSettings settings_;
   LayerTreeDebugState debug_state_;
   bool visible_;