Prevent create ScrollbarAnimationController for Mac Overlay Scrollbar

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 8f1158a43028672145c9780774844f607ab8df27..dec06bab11eb8c2b290381b40713164b261dbc32 100644
--- a/cc/trees/layer_tree_impl.cc
+++ b/cc/trees/layer_tree_impl.cc
@@ -1707,7 +1707,9 @@ void LayerTreeImpl::RegisterScrollbar(ScrollbarLayerImplBase* scrollbar_layer) {
     scrollbar_ids.vertical = scrollbar_layer->id();
   }
 
-  if (IsActiveTree() && scrollbar_layer->is_overlay_scrollbar()) {
+  if (IsActiveTree() && scrollbar_layer->is_overlay_scrollbar() &&
+      scrollbar_layer->GetScrollbarAnimator() !=
+          LayerTreeSettings::NO_ANIMATOR) {
     layer_tree_host_impl_->RegisterScrollbarAnimationController(
         scroll_element_id, scrollbar_layer->Opacity());
   }