Removing `preference` field from `cricket::Codec`.

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 739 matching lines @@
 
   // Handle send codec.
   const std::vector<VideoCodecSettings> supported_codecs =
       FilterSupportedCodecs(MapCodecs(params.codecs));
 
   if (supported_codecs.empty()) {
     LOG(LS_ERROR) << "No video codecs supported.";
     return false;
   }
 
-  if (!send_codec_ || supported_codecs.front() != *send_codec_) {
-    changed_params->codec =
-        rtc::Optional<VideoCodecSettings>(supported_codecs.front());
+  VideoCodecSettings new_codec = supported_codecs.front();
+  // Preference doesn't matter at this point and shouldn't impact comparison.
+  new_codec.codec.preference = 0;

[pbos-webrtc, 2016/04/04 07:58:58]

Can we change VideoCodecSettings instead to not contain a cricket::VideoCodec
but only the parts of it that we need?

+  if (!send_codec_ || new_codec != *send_codec_) {
+    changed_params->codec = rtc::Optional<VideoCodecSettings>(new_codec);
   }
 
   // Handle RTP header extensions.
   std::vector<webrtc::RtpExtension> filtered_extensions = FilterRtpExtensions(
       params.extensions, webrtc::RtpExtension::IsSupportedForVideo, true);
   if (send_rtp_extensions_ != filtered_extensions) {
     changed_params->rtp_header_extensions =
         rtc::Optional<std::vector<webrtc::RtpExtension>>(filtered_extensions);
   }
 
@@ skipping 1820 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