Move webaudio to oilpan

Source/modules/webaudio/AudioNode.cpp

Index: Source/modules/webaudio/AudioNode.cpp
diff --git a/Source/modules/webaudio/AudioNode.cpp b/Source/modules/webaudio/AudioNode.cpp
index b6892a3f2a6238e5fcd1c9f50f367feff57ff15c..37bb3cb61a5c6dd9bd3d715f5a4ab90e6166089b 100644
--- a/Source/modules/webaudio/AudioNode.cpp
+++ b/Source/modules/webaudio/AudioNode.cpp
@@ -48,6 +48,9 @@ AudioNode::AudioNode(AudioContext* context, float sampleRate)
     , m_nodeType(NodeTypeUnknown)
     , m_context(context)
     , m_sampleRate(sampleRate)
+#if ENABLE(OILPAN)
+    , m_keepAlive(adoptPtr(new Persistent<AudioNode>(this)))
+#endif
     , m_lastProcessingTime(-1)
     , m_lastNonSilentTime(-1)
     , m_normalRefCount(1) // start out with normal refCount == 1 (like WTF::RefCounted class)
@@ -473,6 +476,9 @@ void AudioNode::disableOutputsIfNecessary()
 
 void AudioNode::ref(RefType refType)
 {
+#if ENABLE(OILPAN)
+    ASSERT(m_keepAlive);
+#endif
     switch (refType) {
     case RefTypeNormal:
         atomicIncrement(&m_normalRefCount);
@@ -587,6 +593,24 @@ void AudioNode::printNodeCounts()
 
 #endif // DEBUG_AUDIONODE_REFERENCES
 
+void AudioNode::trace(Visitor* visitor)
+{
+    visitor->trace(m_context);
+}
+
+#if ENABLE(OILPAN)
+void AudioNode::clearKeepAlive()
+{
+    // It is safe to drop the self-persistent when the ref count
+    // of a AudioNode reaches zero. At that point, the
+    // AudioNode node is removed from the AudioContext and
+    // it cannot be reattached. Therefore, the reference count
+    // will not go above zero again.
+    ASSERT(m_keepAlive);
+    m_keepAlive = nullptr;
+}
+#endif
+
 } // namespace WebCore
 
 #endif // ENABLE(WEB_AUDIO)