cc: Move TryScroll from LayerImpl to LayerTreeHostImpl

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 dac4c9201c3aa731c05694f4ced8896e92c4dc95..001ace6f9bef869731f845e155c12b2dd9df2b80 100644
--- a/cc/trees/property_tree.h
+++ b/cc/trees/property_tree.h
@@ -275,6 +275,7 @@ struct CC_EXPORT ScrollNodeData {
   bool max_scroll_offset_affected_by_page_scale;
   bool is_inner_viewport_scroll_layer;
   bool is_outer_viewport_scroll_layer;
+  int transform_id;
 
   bool operator==(const ScrollNodeData& other) const;
 
@@ -530,6 +531,7 @@ class CC_EXPORT ScrollTree final : public PropertyTree<ScrollNode> {
   void FromProtobuf(const proto::PropertyTree& proto);
 
   gfx::ScrollOffset MaxScrollOffset(int scroll_node_id) const;
+  gfx::Transform ScreenSpaceTransform(int scroll_node_id) const;
 };
 
 class CC_EXPORT PropertyTrees final {