Oilpan: trace Event.currentTarget.

Source/core/xml/XMLHttpRequestProgressEventThrottle.h

 /*
  * Copyright (C) 2010 Julien Chaffraix <jchaffraix@webkit.org>
  * All right 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 63 matching lines @@
     // Dispatches an event. If suspended, just queues the given event.
     void dispatchEvent(PassRefPtrWillBeRawPtr<Event>);
 
     virtual void fired() OVERRIDE;
     void dispatchDeferredEvents(Timer<XMLHttpRequestProgressEventThrottle>*);
     bool flushDeferredProgressEvent();
     void deliverProgressEvent();
 
     bool hasEventToDispatch() const;
 
-    // Weak pointer to our XMLHttpRequest object as it is the one holding us.
-    EventTarget* m_target;
+    // Non-Oilpan, keep a weak pointer to our XMLHttpRequest object as it is
+    // the one holding us. With Oilpan, a simple strong Member can be used -
+    // this XMLHttpRequestProgressEventThrottle (part) object dies together
+    // with the XMLHttpRequest object.
+    RawPtrWillBeMember<EventTarget> m_target;
 
     bool m_lengthComputable;
     unsigned long long m_loaded;
     unsigned long long m_total;
 
     bool m_deferEvents;
     RefPtrWillBeMember<Event> m_deferredProgressEvent;
     WillBeHeapVector<RefPtrWillBeMember<Event> > m_deferredEvents;
     Timer<XMLHttpRequestProgressEventThrottle> m_dispatchDeferredEventsTimer;
 };
 
 } // namespace WebCore
 
 #endif // XMLHttpRequestProgressEventThrottle_h