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..a99b856e7da78c439386f32fd0217d2f793e399f 100644
--- a/third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.cpp
@@ -790,8 +790,20 @@ void AbstractAudioContext::notifySourceNodeStartedProcessing(AudioNode* node)
 void AbstractAudioContext::releaseActiveSourceNodes()
 {
     ASSERT(isMainThread());
-    for (auto& sourceNode : m_activeSourceNodes)
+    AutoLocker locker(this);
+
+    for (AudioNode* sourceNode : m_activeSourceNodes) {
+        // When the execution context is tearing down, we need to mark all the
+        // active scheduled source nodes (i.e. Oscillator, BufferSource) as
+        // 'available for GC' so they can be collected properly.
+        if (sourceNode->handler().nodeType() == AudioHandler::NodeTypeOscillator
+            || sourceNode->handler().nodeType() == AudioHandler::NodeTypeAudioBufferSource) {
+            AudioScheduledSourceNode* scheduledSourceNode = static_cast<AudioScheduledSourceNode*>(sourceNode);
+            scheduledSourceNode->markForGC();
+        }
+
         sourceNode->handler().breakConnection();
+    }
 
     m_activeSourceNodes.clear();
 }