Don't run removeFinishedSourceNodes with the context lock.

third_party/WebKit/Source/modules/webaudio/BaseAudioContext.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 628 matching lines @@
   // Quadratic worst case, but sizes of both vectors are considered
   // manageable, especially |m_finishedSourceNodes| is likely to be short.
   for (AudioNode* node : m_finishedSourceNodes) {
     size_t i = m_activeSourceNodes.find(node);
     if (i != kNotFound)
       m_activeSourceNodes.remove(i);
   }
   m_finishedSourceNodes.clear();
 }
 
-void BaseAudioContext::releaseFinishedSourceNodes() {
+bool BaseAudioContext::releaseFinishedSourceNodes() {
   ASSERT(isGraphOwner());
   DCHECK(isAudioThread());
   bool didRemove = false;
   for (AudioHandler* handler : m_finishedSourceHandlers) {
     for (AudioNode* node : m_activeSourceNodes) {
       if (m_finishedSourceNodes.contains(node))
         continue;
       if (handler == &node->handler()) {
         handler->breakConnection();
         m_finishedSourceNodes.add(node);
         didRemove = true;
         break;
       }
     }
   }
-  if (didRemove)
-    Platform::current()->mainThread()->getWebTaskRunner()->postTask(
-        BLINK_FROM_HERE,
-        crossThreadBind(&BaseAudioContext::removeFinishedSourceNodes,
-                        wrapCrossThreadPersistent(this)));
-
-  m_finishedSourceHandlers.clear();

[hongchan, 2017/01/19 12:47:43]

We don't have this line in the patchset anymore. Is that okay?

[Raymond Toy, 2017/01/20 19:36:10]

Fixed.

+  return didRemove;
 }
 
 void BaseAudioContext::notifySourceNodeStartedProcessing(AudioNode* node) {
   DCHECK(isMainThread());
   AutoLocker locker(this);
 
   m_activeSourceNodes.push_back(node);
   node->handler().makeConnection();
 }
 
@@ skipping 52 matching lines @@
 }
 
 void BaseAudioContext::handlePostRenderTasks() {
   DCHECK(isAudioThread());
 
   // Must use a tryLock() here too.  Don't worry, the lock will very rarely be
   // contended and this method is called frequently.  The worst that can happen
   // is that there will be some nodes which will take slightly longer than usual
   // to be deleted or removed from the render graph (in which case they'll
   // render silence).
+  bool didRemove = false;
   if (tryLock()) {
     // Take care of AudioNode tasks where the tryLock() failed previously.
     deferredTaskHandler().breakConnections();
 
     // Dynamically clean up nodes which are no longer needed.
-    releaseFinishedSourceNodes();
+    didRemove = releaseFinishedSourceNodes();
 
     deferredTaskHandler().handleDeferredTasks();
     deferredTaskHandler().requestToDeleteHandlersOnMainThread();
 
     unlock();
   }
+
+  if (didRemove) {
+    Platform::current()->mainThread()->getWebTaskRunner()->postTask(
+        BLINK_FROM_HERE,
+        crossThreadBind(&BaseAudioContext::removeFinishedSourceNodes,
+                        wrapCrossThreadPersistent(this)));
+  }
 }
 
 void BaseAudioContext::resolvePromisesForResumeOnMainThread() {
   DCHECK(isMainThread());
   AutoLocker locker(this);
 
   for (auto& resolver : m_resumeResolvers) {
     if (m_contextState == Closed) {
       resolver->reject(DOMException::create(
           InvalidStateError, "Cannot resume a context that has been closed"));
@@ skipping 126 matching lines @@
 }
 
 SecurityOrigin* BaseAudioContext::getSecurityOrigin() const {
   if (getExecutionContext())
     return getExecutionContext()->getSecurityOrigin();
 
   return nullptr;
 }
 
 }  // namespace blink