Adding the ability to create an RtpSender without a track.

talk/app/webrtc/peerconnectioninterface_unittest.cc

 /*
  * libjingle
  * Copyright 2012 Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *  1. Redistributions of source code must retain the above copyright notice,
  *     this list of conditions and the following disclaimer.
  *  2. Redistributions in binary form must reproduce the above copyright notice,
@@ skipping 1930 matching lines @@
   pc_->AddStream(reference_collection_->at(0));
   EXPECT_TRUE(DoSetLocalDescription(desc_1.release()));
   auto senders = pc_->GetSenders();
   EXPECT_EQ(4u, senders.size());
   EXPECT_TRUE(ContainsSender(senders, kAudioTracks[0]));
   EXPECT_TRUE(ContainsSender(senders, kVideoTracks[0]));
   EXPECT_TRUE(ContainsSender(senders, kAudioTracks[1]));
   EXPECT_TRUE(ContainsSender(senders, kVideoTracks[1]));
 
   // Remove an audio and video track.
+  pc_->RemoveStream(reference_collection_->at(0));
   rtc::scoped_ptr<SessionDescriptionInterface> desc_2;
   CreateSessionDescriptionAndReference(1, 1, desc_2.accept());
+  pc_->AddStream(reference_collection_->at(0));

[pthatcher1, 2015/10/20 17:42:49]

Was this test wrong before?

[Taylor Brandstetter, 2015/10/21 00:22:08]

No, there's an intentional change in behavior. Previously a sender only existed
if AddStream AND SetLocalDescription were called. But now, createSender must
return a sender even before SetLocalDescription is called. So the bounds of a
sender's lifetime had to change a bit.

   EXPECT_TRUE(DoSetLocalDescription(desc_2.release()));
   senders = pc_->GetSenders();
   EXPECT_EQ(2u, senders.size());
   EXPECT_TRUE(ContainsSender(senders, kAudioTracks[0]));
   EXPECT_TRUE(ContainsSender(senders, kVideoTracks[0]));
   EXPECT_FALSE(ContainsSender(senders, kAudioTracks[1]));
   EXPECT_FALSE(ContainsSender(senders, kVideoTracks[1]));
 }
 
 // This tests that an RtpSender is created when the local description is set
@@ skipping 279 matching lines @@
   EXPECT_TRUE(updated_answer_options.has_video());
 
   RTCOfferAnswerOptions default_rtc_options;
   EXPECT_TRUE(
       ConvertRtcOptionsForOffer(default_rtc_options, &updated_offer_options));
   // By default, |has_audio| or |has_video| are false if there is no media
   // track.
   EXPECT_FALSE(updated_offer_options.has_audio());
   EXPECT_FALSE(updated_offer_options.has_video());
 }