Remove ScrollNode's layer_id_to_scrollbars_enabled_map

cc/trees/property_tree.cc

 // Copyright 2014 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 <stddef.h>
 
 #include <set>
 #include <vector>
 
 #include "base/logging.h"
@@ skipping 1124 matching lines @@
 
   bool is_currently_scrolling_node_equal =
       currently_scrolling_node_id_ == other.currently_scrolling_node_id_;
 
   return PropertyTree::operator==(other) && is_currently_scrolling_node_equal;
 }
 
 #if DCHECK_IS_ON()
 void ScrollTree::CopyCompleteTreeState(const ScrollTree& other) {
   currently_scrolling_node_id_ = other.currently_scrolling_node_id_;
-  layer_id_to_scrollbars_enabled_map_ =
-      other.layer_id_to_scrollbars_enabled_map_;
   layer_id_to_scroll_offset_map_ = other.layer_id_to_scroll_offset_map_;
   layer_id_to_synced_scroll_offset_map_ =
       other.layer_id_to_synced_scroll_offset_map_;
 }
 #endif
 
 void ScrollTree::clear() {
   PropertyTree<ScrollNode>::clear();
 
   if (property_trees()->is_main_thread) {
@@ skipping 939 matching lines @@
 
   const EffectNode* effect_node = effect_tree.Node(effect_id);
 
   bool success = GetFromTarget(transform_id, effect_id, transform);
   transform->Scale(effect_node->surface_contents_scale.x(),
                    effect_node->surface_contents_scale.y());
   return success;
 }
 
 }  // namespace cc