Change cc::ElementId to be a uint64_t

cc/trees/layer_tree_host.h

 // 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.
 
 #ifndef CC_TREES_LAYER_TREE_HOST_H_
 #define CC_TREES_LAYER_TREE_HOST_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 592 matching lines @@
   gfx::Vector2dF elastic_overscroll_;
 
   scoped_refptr<HeadsUpDisplayLayer> hud_layer_;
 
   // Set of layers that need to push properties.
   std::unordered_set<Layer*> layers_that_should_push_properties_;
 
   // Layer id to Layer map.
   std::unordered_map<int, Layer*> layer_id_map_;
 
-  std::unordered_map<ElementId, Layer*, ElementIdHash> element_layers_map_;
+  std::unordered_map<ElementId::Id, Layer*> element_layers_map_;
 
   bool in_paint_layer_contents_ = false;
   bool in_update_property_trees_ = false;
 
   // This is true if atleast one layer in the layer tree has a copy request. We
   // use this bool to decide whether we need to compute subtree has copy request
   // for every layer during property tree building.
   bool has_copy_request_ = false;
 
   MutatorHost* mutator_host_;
 
   std::vector<std::pair<sk_sp<const SkImage>, base::Callback<void(bool)>>>
       queued_image_decodes_;
 
   bool did_navigate_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHost);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_HOST_H_