[wrapper-tracing] MutationObserver: Add write barriers

third_party/WebKit/Source/core/dom/NodeRareData.h

 /*
  * Copyright (C) 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2008 David Smith <catfish.man@gmail.com>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  *
  */
 
 #ifndef NodeRareData_h
 #define NodeRareData_h
 
+#include "bindings/core/v8/ScriptWrappableVisitor.h"
 #include "core/dom/MutationObserverRegistration.h"
 #include "core/dom/NodeListsNodeData.h"
 #include "platform/heap/Handle.h"
 #include "wtf/HashSet.h"
 
 namespace blink {
 
 class NodeMutationObserverData final
     : public GarbageCollected<NodeMutationObserverData> {
   WTF_MAKE_NONCOPYABLE(NodeMutationObserverData);
@@ skipping 42 matching lines @@
     DCHECK(ThreadState::current()->isGCForbidden());
     if (!m_nodeLists)
       m_nodeLists = NodeListsNodeData::create();
     return *m_nodeLists;
   }
 
   NodeMutationObserverData* mutationObserverData() {
     return m_mutationObserverData.get();
   }
   NodeMutationObserverData& ensureMutationObserverData() {
-    if (!m_mutationObserverData)
+    if (!m_mutationObserverData) {
       m_mutationObserverData = NodeMutationObserverData::create();
+      ScriptWrappableVisitor::writeBarrier(this, m_mutationObserverData);
+    }
     return *m_mutationObserverData;
   }
 
   unsigned connectedSubframeCount() const { return m_connectedFrameCount; }
   void incrementConnectedSubframeCount();
   void decrementConnectedSubframeCount() {
     DCHECK(m_connectedFrameCount);
     --m_connectedFrameCount;
   }
 
@@ skipping 41 matching lines @@
   unsigned m_elementFlags : NumberOfElementFlags;
   unsigned m_restyleFlags : NumberOfDynamicRestyleFlags;
 
  protected:
   unsigned m_isElementRareData : 1;
 };
 
 }  // namespace blink
 
 #endif  // NodeRareData_h