Oilpan: Use transition types for HTMLDivElement.

Source/core/html/track/vtt/VTTRegion.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 300 matching lines @@
 }
 
 const AtomicString& VTTRegion::textTrackRegionShadowPseudoId()
 {
     DEFINE_STATIC_LOCAL(const AtomicString, trackRegionShadowPseudoId,
         ("-webkit-media-text-track-region", AtomicString::ConstructFromLiteral));
 
     return trackRegionShadowPseudoId;
 }
 
-PassRefPtr<HTMLDivElement> VTTRegion::getDisplayTree(Document& document)
+PassRefPtrWillBeRawPtr<HTMLDivElement> VTTRegion::getDisplayTree(Document& document)
 {
     if (!m_regionDisplayTree) {
         m_regionDisplayTree = HTMLDivElement::create(document);
         prepareRegionDisplayTree();
     }
 
     return m_regionDisplayTree;
 }
 
 void VTTRegion::willRemoveVTTCueBox(VTTCueBox* box)
@@ skipping 136 matching lines @@
 }
 
 void VTTRegion::trace(Visitor* visitor)
 {
     visitor->trace(m_cueContainer);
     visitor->trace(m_regionDisplayTree);
     visitor->trace(m_track);
 }
 
 } // namespace WebCore