Add PeerConnection IsClosed check.

webrtc/api/peerconnection.cc

Index: webrtc/api/peerconnection.cc
diff --git a/webrtc/api/peerconnection.cc b/webrtc/api/peerconnection.cc
index 581159f13ac312614dbc20fd0c35fb1bf9bd60a4..b6d0138aaf4a0d4c93dae9d4d7e225072473ba0c 100644
--- a/webrtc/api/peerconnection.cc
+++ b/webrtc/api/peerconnection.cc
@@ -591,6 +591,9 @@ bool PeerConnection::Initialize(
       new WebRtcSession(media_controller_.get(), factory_->network_thread(),
                         factory_->worker_thread(), factory_->signaling_thread(),
                         port_allocator_.get()));
+
+  session_->SetTransportController(
+      factory_->CreateTransportController(port_allocator_.get()));
   stats_.reset(new StatsCollector(this));
 
   // Initialize the WebRtcSession. It creates transport channels etc.
@@ -761,6 +764,9 @@ bool PeerConnection::RemoveTrack(RtpSenderInterface* sender) {
 rtc::scoped_refptr<DtmfSenderInterface> PeerConnection::CreateDtmfSender(
     AudioTrackInterface* track) {
   TRACE_EVENT0("webrtc", "PeerConnection::CreateDtmfSender");
+  if (IsClosed()) {
+    return nullptr;
+  }
   if (!track) {
     LOG(LS_ERROR) << "CreateDtmfSender - track is NULL.";
     return NULL;
@@ -783,6 +789,9 @@ rtc::scoped_refptr<RtpSenderInterface> PeerConnection::CreateSender(
     const std::string& kind,
     const std::string& stream_id) {
   TRACE_EVENT0("webrtc", "PeerConnection::CreateSender");
+  if (IsClosed()) {
+    return nullptr;
+  }
   rtc::scoped_refptr<RtpSenderInterface> new_sender;
   if (kind == MediaStreamTrackInterface::kAudioKind) {
     new_sender = RtpSenderProxy::Create(
@@ -985,6 +994,9 @@ void PeerConnection::SetLocalDescription(
     SetSessionDescriptionObserver* observer,
     SessionDescriptionInterface* desc) {
   TRACE_EVENT0("webrtc", "PeerConnection::SetLocalDescription");
+  if (IsClosed()) {
+    return;
+  }
   if (!VERIFY(observer != nullptr)) {
     LOG(LS_ERROR) << "SetLocalDescription - observer is NULL.";
     return;
@@ -1063,6 +1075,9 @@ void PeerConnection::SetRemoteDescription(
     SetSessionDescriptionObserver* observer,
     SessionDescriptionInterface* desc) {
   TRACE_EVENT0("webrtc", "PeerConnection::SetRemoteDescription");
+  if (IsClosed()) {
+    return;
+  }
   if (!VERIFY(observer != nullptr)) {
     LOG(LS_ERROR) << "SetRemoteDescription - observer is NULL.";
     return;
@@ -1179,6 +1194,9 @@ bool PeerConnection::SetConfiguration(const RTCConfiguration& configuration) {
 bool PeerConnection::AddIceCandidate(
     const IceCandidateInterface* ice_candidate) {
   TRACE_EVENT0("webrtc", "PeerConnection::AddIceCandidate");
+  if (IsClosed()) {
+    return false;
+  }
   return session_->ProcessIceMessage(ice_candidate);
 }
 
@@ -1223,7 +1241,6 @@ void PeerConnection::Close() {
   // Update stats here so that we have the most recent stats for tracks and
   // streams before the channels are closed.
   stats_->UpdateStats(kStatsOutputLevelStandard);
-
   session_->Close();
 }
 
@@ -1364,17 +1381,26 @@ void PeerConnection::OnIceGatheringChange(
 
 void PeerConnection::OnIceCandidate(const IceCandidateInterface* candidate) {
   RTC_DCHECK(signaling_thread()->IsCurrent());
+  if (IsClosed()) {
+    return;
+  }
   observer_->OnIceCandidate(candidate);
 }
 
 void PeerConnection::OnIceCandidatesRemoved(
     const std::vector<cricket::Candidate>& candidates) {
   RTC_DCHECK(signaling_thread()->IsCurrent());
+  if (IsClosed()) {
+    return;
+  }
   observer_->OnIceCandidatesRemoved(candidates);
 }
 
 void PeerConnection::OnIceConnectionReceivingChange(bool receiving) {
   RTC_DCHECK(signaling_thread()->IsCurrent());
+  if (IsClosed()) {
+    return;
+  }
   observer_->OnIceConnectionReceivingChange(receiving);
 }
 
@@ -1394,6 +1420,9 @@ void PeerConnection::ChangeSignalingState(
 
 void PeerConnection::OnAudioTrackAdded(AudioTrackInterface* track,
                                        MediaStreamInterface* stream) {
+  if (IsClosed()) {
+    return;
+  }
   auto sender = FindSenderForTrack(track);
   if (sender != senders_.end()) {
     // We already have a sender for this track, so just change the stream_id
@@ -1424,6 +1453,9 @@ void PeerConnection::OnAudioTrackAdded(AudioTrackInterface* track,
 // indefinitely, when we have unified plan SDP.
 void PeerConnection::OnAudioTrackRemoved(AudioTrackInterface* track,
                                          MediaStreamInterface* stream) {
+  if (IsClosed()) {
+    return;
+  }
   auto sender = FindSenderForTrack(track);
   if (sender == senders_.end()) {
     LOG(LS_WARNING) << "RtpSender for track with id " << track->id()
@@ -1436,6 +1468,9 @@ void PeerConnection::OnAudioTrackRemoved(AudioTrackInterface* track,
 
 void PeerConnection::OnVideoTrackAdded(VideoTrackInterface* track,
                                        MediaStreamInterface* stream) {
+  if (IsClosed()) {
+    return;
+  }
   auto sender = FindSenderForTrack(track);
   if (sender != senders_.end()) {
     // We already have a sender for this track, so just change the stream_id
@@ -1458,6 +1493,9 @@ void PeerConnection::OnVideoTrackAdded(VideoTrackInterface* track,
 
 void PeerConnection::OnVideoTrackRemoved(VideoTrackInterface* track,
                                          MediaStreamInterface* stream) {
+  if (IsClosed()) {
+    return;
+  }
   auto sender = FindSenderForTrack(track);
   if (sender == senders_.end()) {
     LOG(LS_WARNING) << "RtpSender for track with id " << track->id()