Fix for scenario where m-line is revived after being set to port 0.

talk/app/webrtc/peerconnection_unittest.cc

Index: talk/app/webrtc/peerconnection_unittest.cc
diff --git a/talk/app/webrtc/peerconnection_unittest.cc b/talk/app/webrtc/peerconnection_unittest.cc
index 3cf66d64d8827b3c4e71887306844904409a3cdb..7e4454301b7f3c8ea320bc0185c2f1f61ecd66ab 100644
--- a/talk/app/webrtc/peerconnection_unittest.cc
+++ b/talk/app/webrtc/peerconnection_unittest.cc
@@ -276,6 +276,12 @@ class PeerConnectionTestClient : public webrtc::PeerConnectionObserver,
     return pc()->signaling_state() == webrtc::PeerConnectionInterface::kStable;
   }
 
+  // Automatically add a stream when receiving in offer, if we don't have one.
+  // Defaults to true.

[pthatcher1, 2015/11/11 00:45:02]

in offer => an offer?

[Taylor Brandstetter, 2015/11/11 01:33:30]

Done.

+  void set_auto_add_stream(bool auto_add_stream) {
+    auto_add_stream_ = auto_add_stream;
+  }
+
   void set_signaling_message_receiver(
       SignalingMessageReceiver* signaling_message_receiver) {
     signaling_message_receiver_ = signaling_message_receiver;
@@ -705,7 +711,7 @@ class PeerConnectionTestClient : public webrtc::PeerConnectionObserver,
 
   void HandleIncomingOffer(const std::string& msg) {
     LOG(INFO) << id_ << "HandleIncomingOffer ";
-    if (NumberOfLocalMediaStreams() == 0) {
+    if (NumberOfLocalMediaStreams() == 0 && auto_add_stream_) {
       // If we are not sending any streams ourselves it is time to add some.
       AddMediaStream(true, true);
     }
@@ -812,6 +818,8 @@ class PeerConnectionTestClient : public webrtc::PeerConnectionObserver,
   rtc::scoped_refptr<webrtc::PeerConnectionFactoryInterface>
       peer_connection_factory_;
 
+  bool auto_add_stream_ = true;
+
   typedef std::pair<std::string, std::string> IceUfragPwdPair;
   std::map<int, IceUfragPwdPair> ice_ufrag_pwd_;
   bool expect_ice_restart_ = false;
@@ -963,7 +971,6 @@ class JsepPeerConnectionP2PTestClient : public testing::Test {
     ASSERT_TRUE_WAIT(SessionActive(), kMaxWaitForActivationMs);
     VerifySessionDescriptions();
 
-
     int audio_frame_count = kEndAudioFrameCount;
     // TODO(ronghuawu): Add test to cover the case of sendonly and recvonly.
     if (!initiating_client_->can_receive_audio() ||
@@ -1562,6 +1569,29 @@ TEST_F(JsepPeerConnectionP2PTestClient, IceRestart) {
   EXPECT_NE(receiver_candidate, receiver_candidate_restart);
 }
 
+// This test sets up a call between two parties with audio, and video.
+// It then renegotiates setting the video m-line to "port 0", then later
+// renegotiates again, enabling video.
+TEST_F(JsepPeerConnectionP2PTestClient, LocalP2PTestVideoDisableEnable) {
+  ASSERT_TRUE(CreateTestClients());
+
+  // Do initial negotiation. Will result in video and audio sendonly m-lines.
+  receiving_client()->set_auto_add_stream(false);
+  initializing_client()->AddMediaStream(true, true);
+  initializing_client()->Negotiate();
+
+  // Negotiate again, disabling the video m-line (receiving client will
+  // set port to 0 due to mandatory "OfferToReceiveVideo: false" constraint).
+  receiving_client()->SetReceiveVideo(false);
+  initializing_client()->Negotiate();
+
+  // Enable video and do negotiation again, making sure video is received
+  // end-to-end.
+  receiving_client()->SetReceiveVideo(true);
+  receiving_client()->AddMediaStream(true, true);
+  LocalP2PTest();
+}
+
 // This test sets up a Jsep call between two parties with external
 // VideoDecoderFactory.
 // TODO(holmer): Disabled due to sometimes crashing on buildbots.