Remove ScrollNode's layer_id_to_scrollbars_enabled_map

cc/trees/property_tree.h

 // 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.
 
 #ifndef CC_TREES_PROPERTY_TREE_H_
 #define CC_TREES_PROPERTY_TREE_H_
 
 #include <stddef.h>
 
 #include <memory>
@@ skipping 343 matching lines @@
 class CC_EXPORT ScrollTree final : public PropertyTree<ScrollNode> {
  public:
   ScrollTree();
   ~ScrollTree();
 
   ScrollTree& operator=(const ScrollTree& from);
   bool operator==(const ScrollTree& other) const;
 
   void clear();
 
-  typedef std::unordered_map<int, bool> ScrollbarsEnabledMap;
-
   gfx::ScrollOffset MaxScrollOffset(int scroll_node_id) const;
   void OnScrollOffsetAnimated(int layer_id,
                               int scroll_tree_index,
                               const gfx::ScrollOffset& scroll_offset,
                               LayerTreeImpl* layer_tree_impl);
   gfx::Size scroll_clip_layer_bounds(int scroll_node_id) const;
   ScrollNode* CurrentlyScrollingNode();
   const ScrollNode* CurrentlyScrollingNode() const;
 #if DCHECK_IS_ON()
   int CurrentlyScrollingNodeId() const;
@@ skipping 52 matching lines @@
 #if DCHECK_IS_ON()
   void CopyCompleteTreeState(const ScrollTree& other);
 #endif
 
  private:
   using ScrollOffsetMap = std::unordered_map<int, gfx::ScrollOffset>;
   using SyncedScrollOffsetMap =
       std::unordered_map<int, scoped_refptr<SyncedScrollOffset>>;
 
   int currently_scrolling_node_id_;
-  ScrollbarsEnabledMap layer_id_to_scrollbars_enabled_map_;
 
   // On the main thread we store the scroll offsets directly since the main
   // thread only needs to keep track of the current main thread state. The impl
   // thread stores a map of SyncedProperty instances in order to track
   // additional state necessary to synchronize scroll changes between the main
   // and impl threads.
   ScrollOffsetMap layer_id_to_scroll_offset_map_;
   SyncedScrollOffsetMap layer_id_to_synced_scroll_offset_map_;
 
   SyncedScrollOffset* GetOrCreateSyncedScrollOffset(int layer_id);
@@ skipping 204 matching lines @@
   DrawTransforms& GetDrawTransforms(int transform_id, int effect_id) const;
   DrawTransformData& FetchDrawTransformsDataFromCache(int transform_id,
                                                       int effect_id) const;
 
   PropertyTreesCachedData cached_data_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_PROPERTY_TREE_H_