Remove VideoEncoder::SetChannelParameters.

The SetChannelParameters function was used when WebRTC supported decoding
with errors, which we no longer do.

This cleanup CL is related to the work tracked by 9946.

Bug: webrtc:9946
Change-Id: Id2d5ed23031388f890c42651bfbe5f79eda701e5
Reviewed-on: https://webrtc-review.googlesource.com/c/108861
Reviewed-by: Stefan Holmer <stefan@webrtc.org>
Reviewed-by: Rasmus Brandt <brandtr@webrtc.org>
Reviewed-by: Niels Moller <nisse@webrtc.org>
Reviewed-by: Sami Kalliomäki <sakal@webrtc.org>
Commit-Queue: Philip Eliasson <philipel@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25505}

modules/video_coding/codecs/h264/h264_encoder_impl.cc

@@ -625,11 +625,6 @@ void H264EncoderImpl::ReportError() {
   has_reported_error_ = true;
 }
 
-int32_t H264EncoderImpl::SetChannelParameters(uint32_t packet_loss,
-                                              int64_t rtt) {
-  return WEBRTC_VIDEO_CODEC_OK;
-}
-
 VideoEncoder::ScalingSettings H264EncoderImpl::GetScalingSettings() const {
   return VideoEncoder::ScalingSettings(kLowH264QpThreshold,
                                        kHighH264QpThreshold);