Keep AudioSourceNode from premature GC with ScriptWrappable::hasPendingActivity()

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

Index: third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.cpp b/third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.cpp
index 9c27d38a878f0101b55878311a927ab82e69fc61..b31dadf93f2368a2418db767ede7ad8bcf3f01bd 100644
--- a/third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.cpp
@@ -790,8 +790,18 @@ void AbstractAudioContext::notifySourceNodeStartedProcessing(AudioNode* node)
 void AbstractAudioContext::releaseActiveSourceNodes()
 {
     ASSERT(isMainThread());
-    for (auto& sourceNode : m_activeSourceNodes)
+    AutoLocker locker(this);
+
+    for (AudioNode* sourceNode : m_activeSourceNodes) {
+
+        // NOTE: this check makes the renderer crash.

[hongchan, 2016/02/19 00:46:47]

It is necessary to half the active source node. Otherwise the source node in the
'playing' or 'scheduled' state will leak. However, this check causes crashes in
several layout tests. Not sure why.

+        if (sourceNode->handler().nodeType() == AudioHandler::NodeTypeOscillator || AudioHandler::NodeTypeAudioBufferSource) {
+            AudioScheduledSourceNode* scheduledSourceNode = static_cast<AudioScheduledSourceNode*>(sourceNode);
+            scheduledSourceNode->releaseFromContext();
+        }
+
         sourceNode->handler().breakConnection();
+    }
 
     m_activeSourceNodes.clear();
 }