Refactor Scroll Customization to share cc::ScrollStateData with blink.

cc/trees/layer_tree_impl.cc

Index: cc/trees/layer_tree_impl.cc
diff --git a/cc/trees/layer_tree_impl.cc b/cc/trees/layer_tree_impl.cc
index 46561da920d67ada5df4ccbb8314cf19304699e9..53642e4205f615504a75534f65e93634a5d50b37 100644
--- a/cc/trees/layer_tree_impl.cc
+++ b/cc/trees/layer_tree_impl.cc
@@ -1860,7 +1860,8 @@ void LayerTreeImpl::GetViewportSelection(ViewportSelection* selection) {
 
 void LayerTreeImpl::InputScrollAnimationFinished() {
   // TODO(majidvp): We should pass in the original starting scroll position here
-  ScrollState scroll_state(0, 0, 0, 0, 0, 0, false, false, false);
+  ScrollStateData scroll_state_data;
+  ScrollState scroll_state(scroll_state_data);
   layer_tree_host_impl_->ScrollEnd(&scroll_state);
 }