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..a5de70933aa69e18efeca99b0ea9e1ece5940ecd 100644
--- a/Source/modules/mediastream/RTCPeerConnection.h
+++ b/Source/modules/mediastream/RTCPeerConnection.h
@@ -104,6 +104,10 @@ public:
 
     void close(ExceptionState&);
 
+    // We allow getStats after close, but not other calls or callbacks.
+    bool requestMayFireNonStatsCallback() { return !m_closed && !m_stopped; }
+    bool requestMayFireStatsCallback() { return !m_stopped; }
+
     DEFINE_ATTRIBUTE_EVENT_LISTENER(negotiationneeded);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(icecandidate);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(signalingstatechange);
@@ -131,7 +135,20 @@ public:
     virtual void suspend() OVERRIDE;
     virtual void resume() OVERRIDE;
     virtual void stop() OVERRIDE;
-    virtual bool hasPendingActivity() const OVERRIDE { return !m_stopped; }
+    // We require a call to close() or stop() before the object can be garbage
+    // collected. In close(), stop() is called on |m_peer_handler|, after which
+    // no events are fired on this object
+    // (blink::WebRTCPeerConnectionHandlerClient interface). In stop(),
+    // |m_peer_handler| is deleted. Note that async operations such as
+    // createOffer or getStats doesn't respond through this object, but through
+    // a request object containing the callback. The request object is handed to
+    // the client. Hence, we don't need to keep track of if there are still
+    // outstandning requests. The request is given a pointer to this object and
+    // checks if it should fire the callback before doing so.
+    virtual bool hasPendingActivity() const OVERRIDE
+    {
+        return !m_closed && !m_stopped;
+    }
 
     virtual void trace(Visitor*) OVERRIDE;
 
@@ -161,7 +178,12 @@ private:
     AsyncMethodRunner<RTCPeerConnection> m_dispatchScheduledEventRunner;
     WillBeHeapVector<RefPtrWillBeMember<Event> > m_scheduledEvents;
 
+#if !ENABLE(OILPAN)
+    WeakPtrFactory<RTCPeerConnection> m_weakPtrFactory;
+#endif
+
     bool m_stopped;
+    bool m_closed;
 };
 
 } // namespace WebCore