Prevent create ScrollbarAnimationController for Mac Overlay Scrollbar

cc/trees/layer_tree_impl.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/trees/layer_tree_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 1654 matching lines @@
   if (scrollbar_layer->orientation() == HORIZONTAL) {
     DCHECK_EQ(scrollbar_ids.horizontal, Layer::INVALID_ID)
         << "Existing scrollbar should have been unregistered.";
     scrollbar_ids.horizontal = scrollbar_layer->id();
   } else {
     DCHECK_EQ(scrollbar_ids.vertical, Layer::INVALID_ID)
         << "Existing scrollbar should have been unregistered.";
     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());
   }
 
   // TODO(pdr): Refactor DidUpdateScrollState to use ElementIds instead of
   // layer ids and remove this use of LayerIdByElementId.
   DidUpdateScrollState(LayerIdByElementId(scroll_element_id));
 }
 
 void LayerTreeImpl::UnregisterScrollbar(
@@ skipping 431 matching lines @@
 
 void LayerTreeImpl::ResetAllChangeTracking() {
   layers_that_should_push_properties_.clear();
   // Iterate over all layers, including masks.
   for (auto& layer : *layers_)
     layer->ResetChangeTracking();
   property_trees_.ResetAllChangeTracking();
 }
 
 }  // namespace cc