message: Don't configure video codec switching if no video stream has been created.
  Cr-Commit-Position: refs/heads/master@{#29798}
diff: @@ -4147,9 +4147,12 @@ RTCError PeerConnection::SetConfiguration(
  }
  if (modified_config.allow_codec_switching.has_value()) {
  - video_media_channel()->SetVideoCodecSwitchingEnabled(
  + cricket::VideoMediaChannel* video_channel = video_media_channel();
  + if (video_channel) {
  + video_channel->SetVideoCodecSwitchingEnabled(
  *modified_config.allow_codec_switching);
  }
  + }
  configuration_ = modified_config;
  use_media_transport_ = configuration.use_media_transport;
  