Avoid element id collisions with the visual viewport

third_party/WebKit/Source/core/frame/VisualViewport.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 373 matching lines @@
     // Set masks to bounds so the compositor doesn't clobber a manually
     // set inner viewport container layer size.
     m_innerViewportContainerLayer->setMasksToBounds(
         frameHost().settings().mainFrameClipsContent());
     m_innerViewportContainerLayer->setSize(FloatSize(m_size));
 
     m_innerViewportScrollLayer->platformLayer()->setScrollClipLayer(
         m_innerViewportContainerLayer->platformLayer());
     m_innerViewportScrollLayer->platformLayer()->setUserScrollable(true, true);
     if (mainFrame()) {
-      if (Document* document = mainFrame()->document())
+      if (Document* document = mainFrame()->document()) {
         m_innerViewportScrollLayer->setElementId(createCompositorElementId(
-            DOMNodeIds::idForNode(document), CompositorSubElementId::Scroll));
+            DOMNodeIds::idForNode(document), CompositorSubElementId::Viewport));
+      }
     }
 
     m_rootTransformLayer->addChild(m_innerViewportContainerLayer.get());
     m_innerViewportContainerLayer->addChild(m_overscrollElasticityLayer.get());
     m_overscrollElasticityLayer->addChild(m_pageScaleLayer.get());
     m_pageScaleLayer->addChild(m_innerViewportScrollLayer.get());
 
     // Ensure this class is set as the scroll layer's ScrollableArea.
     coordinator->scrollableAreaScrollLayerDidChange(this);
 
@@ skipping 416 matching lines @@
   } else if (graphicsLayer == m_rootTransformLayer.get()) {
     name = "Root Transform Layer";
   } else {
     ASSERT_NOT_REACHED();
   }
 
   return name;
 }
 
 }  // namespace blink