Implement suspend() and resume() for OfflineAudioContext

third_party/WebKit/Source/modules/webaudio/DeferredTaskHandler.cpp

 /*
  * Copyright (C) 2010, 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
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@@ skipping 42 matching lines @@
         return true;
     }
     return m_contextGraphMutex.tryLock();
 }
 
 void DeferredTaskHandler::unlock()
 {
     m_contextGraphMutex.unlock();
 }
 
+void DeferredTaskHandler::offlineLock()
+{
+    // It is safe to lock the audio thread for offline rendering.
+    ASSERT(isAudioThread());

[Raymond Toy, 2015/10/16 23:32:36]

What should we do in a release build if we accidentally do call this from the
audio thread?  It seems pretty bad if this is called from the audio thread.

[hongchan, 2015/10/19 20:08:12]

This is why I completely separated the render method for the offline audio
context. So there is no possibility this method gets called by the realtime
context. However, I can agree with your concern.

We can always use tryLock() if the current thread is not audio thread. WDYT?

[Raymond Toy, 2015/10/19 20:27:27]

Maybe RELEASE_ASSERT or RELEASE_ASSERT_WITH_MESSAGE?

[hongchan, 2015/10/20 22:03:06]

Done.

+    m_contextGraphMutex.lock();
+}
+
 #if ENABLE(ASSERT)
 bool DeferredTaskHandler::isGraphOwner()
 {
     return m_contextGraphMutex.locked();
 }
 #endif
 
 void DeferredTaskHandler::addDeferredBreakConnection(AudioHandler& node)
 {
     ASSERT(isAudioThread());
@@ skipping 188 matching lines @@
 {
     ASSERT(isMainThread());
     AutoLocker locker(*this);
     m_renderingOrphanHandlers.clear();
     m_deletableOrphanHandlers.clear();
 }
 
 } // namespace blink
 
 #endif // ENABLE(WEB_AUDIO)