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

Source/modules/mediastream/MediaStream.h

Index: Source/modules/mediastream/MediaStream.h
diff --git a/Source/modules/mediastream/MediaStream.h b/Source/modules/mediastream/MediaStream.h
index 0511f6e4a627b274a315b775b5d0dd88e6faec5b..f25deb948dd8e1e225e5582b76776a1265000512 100644
--- a/Source/modules/mediastream/MediaStream.h
+++ b/Source/modules/mediastream/MediaStream.h
@@ -40,8 +40,9 @@ namespace WebCore {
 
 class ExceptionState;
 
-class MediaStream FINAL : public RefCounted<MediaStream>, public ScriptWrappable, public URLRegistrable, public MediaStreamDescriptorClient, public EventTargetWithInlineData, public ContextLifecycleObserver, public MediaStreamTrack::Observer {
+class MediaStream FINAL : public RefCountedWillBeRefCountedGarbageCollected<MediaStream>, public ScriptWrappable, public URLRegistrable, public MediaStreamDescriptorClient, public EventTargetWithInlineData, public ContextLifecycleObserver, public MediaStreamTrack::Observer {
     REFCOUNTED_EVENT_TARGET(MediaStream);
+    WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(MediaStream);
 public:
     static PassRefPtr<MediaStream> create(ExecutionContext*);
     static PassRefPtr<MediaStream> create(ExecutionContext*, PassRefPtr<MediaStream>);
@@ -84,6 +85,8 @@ public:
     // URLRegistrable
     virtual URLRegistry& registry() const OVERRIDE;
 
+    virtual void trace(Visitor*) OVERRIDE;
+
 private:
     MediaStream(ExecutionContext*, PassRefPtr<MediaStreamDescriptor>);
     MediaStream(ExecutionContext*, const MediaStreamTrackVector& audioTracks, const MediaStreamTrackVector& videoTracks);
@@ -105,7 +108,7 @@ private:
     RefPtr<MediaStreamDescriptor> m_descriptor;
 
     Timer<MediaStream> m_scheduledEventTimer;
-    WillBePersistentHeapVector<RefPtrWillBeMember<Event> > m_scheduledEvents;
+    WillBeHeapVector<RefPtrWillBeMember<Event> > m_scheduledEvents;
 };
 
 typedef Vector<RefPtr<MediaStream> > MediaStreamVector;