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

third_party/WebKit/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 110 matching lines @@
     , m_pendingRemoveStart(-1)
     , m_pendingRemoveEnd(-1)
     , m_removeAsyncPartRunner(AsyncMethodRunner<SourceBuffer>::create(this, &SourceBuffer::removeAsyncPart))
     , m_streamMaxSizeValid(false)
     , m_streamMaxSize(0)
     , m_appendStreamAsyncPartRunner(AsyncMethodRunner<SourceBuffer>::create(this, &SourceBuffer::appendStreamAsyncPart))
 {
     ASSERT(m_webSourceBuffer);
     ASSERT(m_source);
     ASSERT(m_source->mediaElement());
+    ThreadState::current()->registerPreFinalizer(this);
     m_audioTracks = AudioTrackList::create(*m_source->mediaElement());
     m_videoTracks = VideoTrackList::create(*m_source->mediaElement());
     m_webSourceBuffer->setClient(this);
 }
 
 SourceBuffer::~SourceBuffer()
 {
-    // Oilpan: a SourceBuffer might be finalized without having been
-    // explicitly removed first, hence the asserts below will not
-    // hold.
-#if !ENABLE(OILPAN)
-    m_audioTracks->shutdown();
-    m_videoTracks->shutdown();
-    ASSERT(isRemoved());
-    ASSERT(!m_loader);
-    ASSERT(!m_stream);
-    ASSERT(!m_webSourceBuffer);
-#endif
     WTF_LOG(Media, "SourceBuffer(%p)::~SourceBuffer", this);
 }
 
+void SourceBuffer::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_webSourceBuffer.clear();
+}
+
 const AtomicString& SourceBuffer::segmentsKeyword()
 {
     DEFINE_STATIC_LOCAL(const AtomicString, segments, ("segments"));
     return segments;
 }
 
 const AtomicString& SourceBuffer::sequenceKeyword()
 {
     DEFINE_STATIC_LOCAL(const AtomicString, sequence, ("sequence"));
     return sequence;
@@ skipping 796 matching lines @@
     visitor->trace(m_removeAsyncPartRunner);
     visitor->trace(m_appendStreamAsyncPartRunner);
     visitor->trace(m_stream);
     visitor->trace(m_audioTracks);
     visitor->trace(m_videoTracks);
     RefCountedGarbageCollectedEventTargetWithInlineData<SourceBuffer>::trace(visitor);
     ActiveDOMObject::trace(visitor);
 }
 
 } // namespace blink