Change cc::ElementId to be a uint64_t

cc/test/animation_timelines_test_common.h

 // Copyright 2015 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_TEST_ANIMATION_TIMELINES_TEST_COMMON_H_
 #define CC_TEST_ANIMATION_TIMELINES_TEST_COMMON_H_
 
 #include <memory>
 #include <unordered_map>
 
@@ skipping 161 matching lines @@
                                       int transform_x,
                                       int transform_y) const;
 
   TestLayer* FindTestLayer(ElementId element_id,
                            ElementListType list_type) const;
 
  private:
   std::unique_ptr<AnimationHost> host_;
 
   using ElementIdToTestLayer =
-      std::unordered_map<ElementId, std::unique_ptr<TestLayer>, ElementIdHash>;
+      std::unordered_map<ElementId, std::unique_ptr<TestLayer>>;
   ElementIdToTestLayer layers_in_active_tree_;
   ElementIdToTestLayer layers_in_pending_tree_;
 
   gfx::ScrollOffset scroll_offset_;
   bool mutators_need_commit_;
 };
 
 class TestAnimationDelegate : public AnimationDelegate {
  public:
   TestAnimationDelegate();
@@ skipping 81 matching lines @@
   scoped_refptr<ElementAnimations> element_animations_;
 
   scoped_refptr<AnimationTimeline> timeline_impl_;
   scoped_refptr<AnimationPlayer> player_impl_;
   scoped_refptr<ElementAnimations> element_animations_impl_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TEST_ANIMATION_TIMELINES_TEST_COMMON_H_