cc: Move OnScrollOffsetAnimated to scroll tree

cc/trees/property_tree.h

Index: cc/trees/property_tree.h
diff --git a/cc/trees/property_tree.h b/cc/trees/property_tree.h
index 4f3a501cc20bf46b5538ee84d3875b78a3438c86..9f2bd8571683351b84d8ae370e02cdc5dc89a584 100644
--- a/cc/trees/property_tree.h
+++ b/cc/trees/property_tree.h
@@ -399,6 +399,11 @@ class CC_EXPORT ScrollTree final : public PropertyTree<ScrollNode> {
       ScrollOffsetMap;
 
   gfx::ScrollOffset MaxScrollOffset(int scroll_node_id) const;
+  void OnScrollOffsetAnimated(int layer_id,
+                              int transform_tree_index,
+                              int scroll_tree_index,
+                              const gfx::ScrollOffset& scroll_offset,
+                              LayerTreeImpl* layer_tree_impl);
   gfx::Size scroll_clip_layer_bounds(int scroll_node_id) const;
   ScrollNode* CurrentlyScrollingNode();
   const ScrollNode* CurrentlyScrollingNode() const;