Oilpan: Replace most of RefPtrs for Event objects with oilpan's transition types

Source/modules/mediasource/SourceBuffer.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 463 matching lines @@
 
 bool SourceBuffer::isRemoved() const
 {
     return !m_source;
 }
 
 void SourceBuffer::scheduleEvent(const AtomicString& eventName)
 {
     ASSERT(m_asyncEventQueue);
 
-    RefPtr<Event> event = Event::create(eventName);
+    RefPtrWillBeRawPtr<Event> event = Event::create(eventName);
     event->setTarget(this);
 
     m_asyncEventQueue->enqueueEvent(event.release());
 }
 
 void SourceBuffer::appendBufferInternal(const unsigned char* data, unsigned size, ExceptionState& exceptionState)
 {
     // Section 3.2 appendBuffer()
     // https://dvcs.w3.org/hg/html-media/raw-file/default/media-source/media-source.html#widl-SourceBuffer-appendBuffer-void-ArrayBufferView-data
 
@@ skipping 212 matching lines @@
     appendStreamDone(false);
 }
 
 void SourceBuffer::trace(Visitor* visitor)
 {
     visitor->trace(m_source);
     visitor->trace(m_stream);
 }
 
 } // namespace WebCore