Oilpan: add transition types to FileSystem APIs.

Source/modules/filesystem/FileWriterBase.h

 /*
  * Copyright (C) 2010 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 13 matching lines @@
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef FileWriterBase_h
 #define FileWriterBase_h
 
+#include "heap/Handle.h"
 #include "wtf/OwnPtr.h"
 #include "wtf/PassOwnPtr.h"
 #include "wtf/RefCounted.h"
 
 namespace blink { class WebFileWriter; }
 
 namespace WebCore {
 
-class FileWriterBase : public RefCounted<FileWriterBase> {
+class FileWriterBase : public RefCountedWillBeRefCountedGarbageCollected<FileWriterBase> {
 public:
     virtual ~FileWriterBase();
     void initialize(PassOwnPtr<blink::WebFileWriter>, long long length);
 
     long long position() const
     {
         return m_position;
     }
     long long length() const
     {
         return m_length;
     }
 
+    virtual void trace(Visitor*) { }
+
 protected:
     FileWriterBase();
 
     blink::WebFileWriter* writer()
     {
         return m_writer.get();
     }
 
     void setPosition(long long position)
     {
@@ skipping 11 matching lines @@
     friend class WTF::RefCounted<FileWriterBase>;
 
     OwnPtr<blink::WebFileWriter> m_writer;
     long long m_position;
     long long m_length;
 };
 
 } // namespace WebCore
 
 #endif // FileWriterBase_h