Oilpan: Prepare to move SQLTransactionWrapper and CangeVersionWrapper to Oilpan heap.

Source/modules/webdatabase/ChangeVersionWrapper.h

 /*
  * Copyright (C) 2007, 2013 Apple 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 20 matching lines @@
 #include "heap/Handle.h"
 #include "modules/webdatabase/SQLTransactionBackend.h"
 #include "wtf/Forward.h"
 
 namespace WebCore {
 
 class SQLErrorData;
 
 class ChangeVersionWrapper FINAL : public SQLTransactionWrapper {
 public:
-    static PassRefPtr<ChangeVersionWrapper> create(const String& oldVersion, const String& newVersion) { return adoptRef(new ChangeVersionWrapper(oldVersion, newVersion)); }
+    static PassRefPtrWillBeRawPtr<ChangeVersionWrapper> create(const String& oldVersion, const String& newVersion) { return adoptRefWillBeNoop(new ChangeVersionWrapper(oldVersion, newVersion)); }
 
+    virtual void trace(Visitor*) OVERRIDE { }
     virtual bool performPreflight(SQLTransactionBackend*) OVERRIDE;
     virtual bool performPostflight(SQLTransactionBackend*) OVERRIDE;
     virtual SQLErrorData* sqlError() const OVERRIDE { return m_sqlError.get(); }
     virtual void handleCommitFailedAfterPostflight(SQLTransactionBackend*) OVERRIDE;
 
 private:
     ChangeVersionWrapper(const String& oldVersion, const String& newVersion);
 
     String m_oldVersion;
     String m_newVersion;
     OwnPtr<SQLErrorData> m_sqlError;
 };
 
 } // namespace WebCore
 
 #endif // ChangeVersionWrapper_h