Add PeerConnection IsClosed check.

webrtc/api/peerconnectionfactory.cc

Index: webrtc/api/peerconnectionfactory.cc
diff --git a/webrtc/api/peerconnectionfactory.cc b/webrtc/api/peerconnectionfactory.cc
index 178c59bb1217d22ac43d3d27d388f6da3ea9fcb6..a51ae4a92d171fc50c92bee5bc9873bffe155963 100644
--- a/webrtc/api/peerconnectionfactory.cc
+++ b/webrtc/api/peerconnectionfactory.cc
@@ -159,7 +159,6 @@ bool PeerConnectionFactory::Initialize() {
 
   return true;
 }
-

[Taylor Brandstetter, 2016/06/21 23:50:02]

Was this line deleted on purpose?

 rtc::scoped_refptr<AudioSourceInterface>
 PeerConnectionFactory::CreateAudioSource(
     const MediaConstraintsInterface* constraints) {
@@ -300,6 +299,13 @@ webrtc::MediaControllerInterface* PeerConnectionFactory::CreateMediaController(
                                           channel_manager_.get());
 }
 
+cricket::TransportController* PeerConnectionFactory::CreateTransportController(
+    cricket::PortAllocator* port_allocator) {
+  RTC_DCHECK(signaling_thread_->IsCurrent());
+  return new cricket::TransportController(signaling_thread_, network_thread_,
+                                          port_allocator);
+}
+
 rtc::Thread* PeerConnectionFactory::signaling_thread() {
   // This method can be called on a different thread when the factory is
   // created in CreatePeerConnectionFactory().