Allow PeerConnection to be garbage collected after close().

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 03c6137400bfefde3f731e99e64024106e89e41d..b120053e4e4502ffd6aeea4dd34b831fd56bab3b 100644
--- a/Source/modules/mediastream/RTCPeerConnection.h
+++ b/Source/modules/mediastream/RTCPeerConnection.h
@@ -104,6 +104,8 @@ public:
 
     void close(ExceptionState&);
 
+    bool requestCompletedCheckIfCallbackShouldFire();
+
     DEFINE_ATTRIBUTE_EVENT_LISTENER(negotiationneeded);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(icecandidate);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(signalingstatechange);
@@ -131,7 +133,6 @@ public:
     virtual void suspend() OVERRIDE;
     virtual void resume() OVERRIDE;
     virtual void stop() OVERRIDE;
-    virtual bool hasPendingActivity() const OVERRIDE { return !m_stopped; }
 
     virtual void trace(Visitor*) OVERRIDE;
 
@@ -162,6 +163,7 @@ private:
     WillBeHeapVector<RefPtrWillBeMember<Event> > m_scheduledEvents;
 
     bool m_stopped;
+    bool m_closed;
 };
 
 } // namespace WebCore