Merge 157245 "Fix threading races on ConvolverNode::m_reverb in ..."

Source/modules/webaudio/ConvolverNode.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
  *    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 145 matching lines @@
     return m_buffer.get();
 }
 
 double ConvolverNode::tailTime() const
 {
     return m_reverb ? m_reverb->impulseResponseLength() / static_cast<double>(sampleRate()) : 0;
 }
 
 double ConvolverNode::latencyTime() const
 {
-    return m_reverb ? m_reverb->latencyFrames() / static_cast<double>(sampleRate()) : 0;
+    MutexTryLocker tryLocker(m_processLock);
+    if (tryLocker.locked())
+        return m_reverb ? m_reverb->latencyFrames() / static_cast<double>(sampleRate()) : 0;
+    // Since we don't want to block the Audio Device thread, we return a large value
+    // instead of trying to acquire the lock.
+    return std::numeric_limits<double>::infinity();
 }
 
 } // namespace WebCore
 
 #endif // ENABLE(WEB_AUDIO)