Oilpan: Fix tracing of events through XMLHttpRequestProgressEventThrottle.

Source/core/xml/XMLHttpRequestProgressEventThrottle.h

Index: Source/core/xml/XMLHttpRequestProgressEventThrottle.h
diff --git a/Source/core/xml/XMLHttpRequestProgressEventThrottle.h b/Source/core/xml/XMLHttpRequestProgressEventThrottle.h
index afc55b463141b3b2c95400ff4426433b65bbad37..1ba3db4317a44ff984a0de5d93cb1d36d3b10b22 100644
--- a/Source/core/xml/XMLHttpRequestProgressEventThrottle.h
+++ b/Source/core/xml/XMLHttpRequestProgressEventThrottle.h
@@ -47,6 +47,7 @@ enum ProgressEventAction {
 // This implements the XHR2 progress event dispatching: "dispatch a progress event called progress
 // about every 50ms or for every byte received, whichever is least frequent".
 class XMLHttpRequestProgressEventThrottle FINAL : public TimerBase {
+    DISALLOW_ALLOCATION();
 public:
     explicit XMLHttpRequestProgressEventThrottle(EventTarget*);
     virtual ~XMLHttpRequestProgressEventThrottle();
@@ -59,6 +60,8 @@ public:
     void suspend();
     void resume();
 
+    void trace(Visitor*);
+
 private:
     static const double minimumProgressEventDispatchingIntervalInSeconds;
 
@@ -77,8 +80,8 @@ private:
     unsigned long long m_total;
 
     bool m_deferEvents;
-    RefPtrWillBePersistent<Event> m_deferredProgressEvent;
-    WillBePersistentHeapVector<RefPtrWillBeMember<Event> > m_deferredEvents;
+    RefPtrWillBeMember<Event> m_deferredProgressEvent;
+    WillBeHeapVector<RefPtrWillBeMember<Event> > m_deferredEvents;
     Timer<XMLHttpRequestProgressEventThrottle> m_dispatchDeferredEventsTimer;
 };