Tried to move AudioSummingJuction to oilpan

Source/modules/webaudio/AudioSummingJunction.h

Index: Source/modules/webaudio/AudioSummingJunction.h
diff --git a/Source/modules/webaudio/AudioSummingJunction.h b/Source/modules/webaudio/AudioSummingJunction.h
index d3f392538fd99da9877d2912770dc8b3ccefd5ac..6301682687ddb1d6c77179b14a757e258979008a 100644
--- a/Source/modules/webaudio/AudioSummingJunction.h
+++ b/Source/modules/webaudio/AudioSummingJunction.h
@@ -26,6 +26,7 @@
 #define AudioSummingJunction_h
 
 #include "platform/audio/AudioBus.h"
+#include "platform/heap/Handle.h"
 #include "wtf/HashSet.h"
 #include "wtf/Vector.h"
 
@@ -36,10 +37,9 @@ class AudioNodeOutput;
 
 // An AudioSummingJunction represents a point where zero, one, or more AudioNodeOutputs connect.
 
-class AudioSummingJunction {
+class AudioSummingJunction : public RefCountedWillBeGarbageCollected<AudioSummingJunction> {
 public:
     explicit AudioSummingJunction(AudioContext*);
-    virtual ~AudioSummingJunction();
 
     // Can be called from any thread.
     AudioContext* context() { return m_context.get(); }
@@ -59,8 +59,10 @@ public:
     virtual bool canUpdateState() = 0;
     virtual void didUpdate() = 0;
 
+    virtual void trace(Visitor*);
+
 protected:
-    RefPtr<AudioContext> m_context;
+    RefPtrWillBeMember<AudioContext> m_context;
 
     // m_outputs contains the AudioNodeOutputs representing current connections which are not disabled.
     // The rendering code should never use this directly, but instead uses m_renderingOutputs.