MediaStreamSource: verify unlocked state when finalizing.

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 37 matching lines @@
                                      bool remote,
                                      ReadyState readyState,
                                      bool requiresConsumer)
     : m_id(id),
       m_type(type),
       m_name(name),
       m_remote(remote),
       m_readyState(readyState),
       m_requiresConsumer(requiresConsumer) {}
 
+MediaStreamSource::~MediaStreamSource() {
+  // Verify that the audio thread isn't consuming audio.
+  // TODO(sof): remove once crbug.com/682945 has been diagnosed.
+  MutexTryLocker tryLocker(m_audioConsumersLock);
+  CHECK(tryLocker.locked());
+}
+
 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;
     copyToVector(m_observers, observers);
     for (auto observer : observers)
       observer->sourceChangedState();
@@ skipping 44 matching lines @@
        it != m_audioConsumers.end(); ++it)
     (*it)->consumeAudio(bus, numberOfFrames);
 }
 
 DEFINE_TRACE(MediaStreamSource) {
   visitor->trace(m_observers);
   visitor->trace(m_audioConsumers);
 }
 
 }  // namespace blink