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

webrtc/media/engine/webrtcvideoengine2.cc

Index: webrtc/media/engine/webrtcvideoengine2.cc
diff --git a/webrtc/media/engine/webrtcvideoengine2.cc b/webrtc/media/engine/webrtcvideoengine2.cc
index cd05f8e6ff5bbe48c820639f10477c8e88dc3306..14393135678a9df057f2cbf875ecf112e38d6f0c 100644
--- a/webrtc/media/engine/webrtcvideoengine2.cc
+++ b/webrtc/media/engine/webrtcvideoengine2.cc
@@ -757,9 +757,11 @@ bool WebRtcVideoChannel2::GetChangedSendParameters(
     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.