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 d1bfa3583abdf637c4155c7f4e1b8172ccbe179b..2c57e5a1f0ee5874fc2ea61ad3f129d057a644c1 100644
--- a/cc/trees/layer_tree_impl.cc
+++ b/cc/trees/layer_tree_impl.cc
@@ -1672,7 +1672,9 @@ 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());
   }