Change cc::ElementId to be a uint64_t

cc/layers/painted_overlay_scrollbar_layer.cc

 // Copyright 2016 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/layers/painted_overlay_scrollbar_layer.h"
 
 #include <algorithm>
 
 #include "base/auto_reset.h"
 #include "cc/base/math_util.h"
@@ skipping 36 matching lines @@
   DCHECK(scrollbar_->UsesNinePatchThumbResource());
 }
 
 PaintedOverlayScrollbarLayer::~PaintedOverlayScrollbarLayer() {}
 
 ElementId PaintedOverlayScrollbarLayer::scroll_element_id() const {
   return scroll_element_id_;
 }
 
 void PaintedOverlayScrollbarLayer::SetScrollElementId(ElementId element_id) {
-  if (element_id == scroll_element_id_)
+  if (element_id.id == scroll_element_id_.id)

[wkorman, 2017/05/08 18:23:24]

Can't we rely on operator== here?

     return;
 
   scroll_element_id_ = element_id;
   SetNeedsFullTreeSync();
 }
 
 bool PaintedOverlayScrollbarLayer::OpacityCanAnimateOnImplThread() const {
   return scrollbar_->IsOverlay();
 }
 
@@ skipping 97 matching lines @@
 
   thumb_resource_ = ScopedUIResource::Create(
       layer_tree_host()->GetUIResourceManager(), UIResourceBitmap(skbitmap));
 
   SetNeedsPushProperties();
 
   return true;
 }
 
 }  // namespace cc