Enable Oilpan by default for webaudio/

Source/modules/webaudio/ChannelSplitterNode.cpp

Index: Source/modules/webaudio/ChannelSplitterNode.cpp
diff --git a/Source/modules/webaudio/ChannelSplitterNode.cpp b/Source/modules/webaudio/ChannelSplitterNode.cpp
index 9e588be5974a821d2d360891fbda4a1461111f65..728ac8bb5c820dde3b2234d02d488c34e6e2ed23 100644
--- a/Source/modules/webaudio/ChannelSplitterNode.cpp
+++ b/Source/modules/webaudio/ChannelSplitterNode.cpp
@@ -34,12 +34,12 @@
 
 namespace blink {
 
-PassRefPtrWillBeRawPtr<ChannelSplitterNode> ChannelSplitterNode::create(AudioContext* context, float sampleRate, unsigned numberOfOutputs)
+ChannelSplitterNode* ChannelSplitterNode::create(AudioContext* context, float sampleRate, unsigned numberOfOutputs)
 {
     if (!numberOfOutputs || numberOfOutputs > AudioContext::maxNumberOfChannels())
-        return nullptr;
+        return 0;
 
-    return adoptRefWillBeNoop(new ChannelSplitterNode(context, sampleRate, numberOfOutputs));
+    return adoptRefCountedGarbageCollected(new ChannelSplitterNode(context, sampleRate, numberOfOutputs));
 }
 
 ChannelSplitterNode::ChannelSplitterNode(AudioContext* context, float sampleRate, unsigned numberOfOutputs)