If encoding is inactive, don't start sending when stream is reconfigured.

webrtc/media/engine/webrtcvideoengine2.cc

 /*
  *  Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 2228 matching lines @@
     LOG(LS_WARNING) << "RTX SSRCs configured but there's no configured RTX "
                        "payload type the set codec. Ignoring RTX.";
     config.rtp.rtx.ssrcs.clear();
   }
   stream_ = call_->CreateVideoSendStream(std::move(config),
                                          parameters_.encoder_config.Copy());
 
   parameters_.encoder_config.encoder_specific_settings = NULL;
   pending_encoder_reconfiguration_ = false;
 
-  if (sending_) {
-    stream_->Start();
-  }
+  // Call stream_->Start() if necessary conditions are met.
+  UpdateSendState();
 }
 
 WebRtcVideoChannel2::WebRtcVideoReceiveStream::WebRtcVideoReceiveStream(
     webrtc::Call* call,
     const StreamParams& sp,
     webrtc::VideoReceiveStream::Config config,
     WebRtcVideoDecoderFactory* external_decoder_factory,
     bool default_stream,
     const std::vector<VideoCodecSettings>& recv_codecs,
     bool red_disabled_by_remote_side)
@@ skipping 432 matching lines @@
         rtx_mapping[video_codecs[i].codec.id] !=
             fec_settings.red_payload_type) {
       video_codecs[i].rtx_payload_type = rtx_mapping[video_codecs[i].codec.id];
     }
   }
 
   return video_codecs;
 }
 
 }  // namespace cricket