Oilpan: Allocate all EventTarget derived types on the manged heap.

Source/modules/mediastream/RTCPeerConnection.h

Index: Source/modules/mediastream/RTCPeerConnection.h
diff --git a/Source/modules/mediastream/RTCPeerConnection.h b/Source/modules/mediastream/RTCPeerConnection.h
index 78f953bfde1154cd6a2633bb2a5a466f76b8d48c..f96ca9ea07f876df24700f644c5c4ced5fcd9873 100644
--- a/Source/modules/mediastream/RTCPeerConnection.h
+++ b/Source/modules/mediastream/RTCPeerConnection.h
@@ -56,8 +56,9 @@ class RTCSessionDescriptionCallback;
 class RTCStatsCallback;
 class VoidCallback;
 
-class RTCPeerConnection FINAL : public RefCounted<RTCPeerConnection>, public ScriptWrappable, public blink::WebRTCPeerConnectionHandlerClient, public EventTargetWithInlineData, public ActiveDOMObject {
+class RTCPeerConnection FINAL : public RefCountedWillBeRefCountedGarbageCollected<RTCPeerConnection>, public ScriptWrappable, public blink::WebRTCPeerConnectionHandlerClient, public EventTargetWithInlineData, public ActiveDOMObject {
     REFCOUNTED_EVENT_TARGET(RTCPeerConnection);
+    WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(RTCPeerConnection);
 public:
     static PassRefPtr<RTCPeerConnection> create(ExecutionContext*, const Dictionary& rtcConfiguration, const Dictionary& mediaConstraints, ExceptionState&);
     virtual ~RTCPeerConnection();
@@ -132,6 +133,8 @@ public:
     virtual void stop() OVERRIDE;
     virtual bool hasPendingActivity() const OVERRIDE { return !m_stopped; }
 
+    virtual void trace(Visitor*) OVERRIDE;
+
 private:
     RTCPeerConnection(ExecutionContext*, PassRefPtr<RTCConfiguration>, blink::WebMediaConstraints, ExceptionState&);
 
@@ -156,7 +159,7 @@ private:
     OwnPtr<blink::WebRTCPeerConnectionHandler> m_peerHandler;
 
     AsyncMethodRunner<RTCPeerConnection> m_dispatchScheduledEventRunner;
-    WillBePersistentHeapVector<RefPtrWillBeMember<Event> > m_scheduledEvents;
+    WillBeHeapVector<RefPtrWillBeMember<Event> > m_scheduledEvents;
 
     bool m_stopped;
 };