Tidy up MediaStreamSource details.

third_party/WebKit/Source/platform/mediastream/MediaStreamSource.cpp

 /*
  * Copyright (C) 2012 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
@@ skipping 28 matching lines @@
 }
 
 MediaStreamSource::MediaStreamSource(const String& id, StreamType type, const String& name, bool remote, ReadyState readyState, bool requiresConsumer)
     : m_id(id)
     , m_type(type)
     , m_name(name)
     , m_remote(remote)
     , m_readyState(readyState)
     , m_requiresConsumer(requiresConsumer)
 {
-    ThreadState::current()->registerPreFinalizer(this);
-}
-
-void MediaStreamSource::dispose()
-{
-    m_extraData.reset();
 }
 
 void MediaStreamSource::setReadyState(ReadyState readyState)
 {
     if (m_readyState != ReadyStateEnded && m_readyState != readyState) {
         m_readyState = readyState;
 
         // Observers may dispatch events which create and add new Observers;
         // take a snapshot so as to safely iterate.
         HeapVector<Member<Observer>> observers;
@@ skipping 42 matching lines @@
         (*it)->consumeAudio(bus, numberOfFrames);
 }
 
 DEFINE_TRACE(MediaStreamSource)
 {
     visitor->trace(m_observers);
     visitor->trace(m_audioConsumers);
 }
 
 } // namespace blink