Oilpan: Replace EAGERLY_FINALIZE in EventTarget's hierarchy with pre-finalizers

third_party/WebKit/Source/modules/mediastream/RTCDTMFSender.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:
  * 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 47 matching lines @@
 
 RTCDTMFSender::RTCDTMFSender(ExecutionContext* context, MediaStreamTrack* track, PassOwnPtr<WebRTCDTMFSenderHandler> handler)
     : ActiveDOMObject(context)
     , m_track(track)
     , m_duration(defaultToneDurationMs)
     , m_interToneGap(defaultInterToneGapMs)
     , m_handler(handler)
     , m_stopped(false)
     , m_scheduledEventTimer(this, &RTCDTMFSender::scheduledEventTimerFired)
 {
+    ThreadState::current()->registerPreFinalizer(this);
     m_handler->setClient(this);
 }
 
 RTCDTMFSender::~RTCDTMFSender()
 {
 }
 
+void RTCDTMFSender::dispose()
+{
+    // Promptly clears a raw reference from content/ to an on-heap object
+    // so that content/ doesn't access it in a lazy sweeping phase.
+    m_handler->setClient(nullptr);
+    m_handler.clear();
+}
+
 bool RTCDTMFSender::canInsertDTMF() const
 {
     return m_handler->canInsertDTMF();
 }
 
 MediaStreamTrack* RTCDTMFSender::track() const
 {
     return m_track.get();
 }
 
@@ skipping 47 matching lines @@
 }
 
 ExecutionContext* RTCDTMFSender::getExecutionContext() const
 {
     return ActiveDOMObject::getExecutionContext();
 }
 
 void RTCDTMFSender::stop()
 {
     m_stopped = true;
-    m_handler->setClient(0);
+    m_handler->setClient(nullptr);
 }
 
 void RTCDTMFSender::scheduleDispatchEvent(Event* event)
 {
     m_scheduledEvents.append(event);
 
     if (!m_scheduledEventTimer.isActive())
         m_scheduledEventTimer.startOneShot(0, BLINK_FROM_HERE);
 }
 
@@ skipping 12 matching lines @@
 
 DEFINE_TRACE(RTCDTMFSender)
 {
     visitor->trace(m_track);
     visitor->trace(m_scheduledEvents);
     RefCountedGarbageCollectedEventTargetWithInlineData<RTCDTMFSender>::trace(visitor);
     ActiveDOMObject::trace(visitor);
 }
 
 } // namespace blink