Don't create remote streams if m-line direction doesn't include "send".

talk/app/webrtc/peerconnection.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 1011 matching lines @@
   // since only at that point will new streams have all their tracks.
   rtc::scoped_refptr<StreamCollection> new_streams(StreamCollection::Create());
 
   // Find all audio rtp streams and create corresponding remote AudioTracks
   // and MediaStreams.
   const cricket::ContentInfo* audio_content = GetFirstAudioContent(remote_desc);
   if (audio_content) {
     const cricket::AudioContentDescription* desc =
         static_cast<const cricket::AudioContentDescription*>(
             audio_content->description);
-    UpdateRemoteStreamsList(desc->streams(), desc->type(), new_streams);
+    // If the direction is "recvonly" or "inactive", treat the description
+    // as containing no streams.
+    // See: https://code.google.com/p/webrtc/issues/detail?id=5054
+    UpdateRemoteStreamsList(MediaContentDirectionHasSend(desc->direction())
+                                ? desc->streams()
+                                : std::vector<cricket::StreamParams>(),

[pthatcher1, 2015/10/15 05:46:49]

Can you put this logic in a method called "GetActiveStreams(desc)"?  We can just
call any streams on a recvonly/inactive line "inactive".

[Taylor Brandstetter, 2015/10/15 17:32:24]

Done.

+                            desc->type(), new_streams);
     remote_info_.default_audio_track_needed =
         MediaContentDirectionHasSend(desc->direction()) &&
         desc->streams().empty();
   }
 
   // Find all video rtp streams and create corresponding remote VideoTracks
   // and MediaStreams.
   const cricket::ContentInfo* video_content = GetFirstVideoContent(remote_desc);
   if (video_content) {
     const cricket::VideoContentDescription* desc =
         static_cast<const cricket::VideoContentDescription*>(
             video_content->description);
-    UpdateRemoteStreamsList(desc->streams(), desc->type(), new_streams);
+    UpdateRemoteStreamsList(MediaContentDirectionHasSend(desc->direction())
+                                ? desc->streams()
+                                : std::vector<cricket::StreamParams>(),
+                            desc->type(), new_streams);
     remote_info_.default_video_track_needed =
         MediaContentDirectionHasSend(desc->direction()) &&
         desc->streams().empty();
   }
 
   // Update the DataChannels with the information from the remote peer.
   const cricket::ContentInfo* data_content = GetFirstDataContent(remote_desc);
   if (data_content) {
-    const cricket::DataContentDescription* data_desc =
+    const cricket::DataContentDescription* desc =
         static_cast<const cricket::DataContentDescription*>(
             data_content->description);
-    if (rtc::starts_with(data_desc->protocol().data(),
+    if (rtc::starts_with(desc->protocol().data(),
                          cricket::kMediaProtocolRtpPrefix)) {
-      UpdateRemoteRtpDataChannels(data_desc->streams());
+      UpdateRemoteRtpDataChannels(
+          MediaContentDirectionHasSend(desc->direction())
+              ? desc->streams()
+              : std::vector<cricket::StreamParams>());
     }
   }
 
   // Iterate new_streams and notify the observer about new MediaStreams.
   for (size_t i = 0; i < new_streams->count(); ++i) {
     MediaStreamInterface* new_stream = new_streams->at(i);
     stats_->AddStream(new_stream);
     observer_->OnAddStream(new_stream);
   }
 
@@ skipping 879 matching lines @@
 DataChannel* PeerConnection::FindDataChannelBySid(int sid) const {
   for (const auto& channel : sctp_data_channels_) {
     if (channel->id() == sid) {
       return channel;
     }
   }
   return nullptr;
 }
 
 }  // namespace webrtc