Audio codec implementations: Take optional codec ID argument

None of the built-in codecs do anything with the ID, but callers will
soon require them to accept it.

Bug: webrtc:8941
Change-Id: I0eb77db82d72c7d34cff639fecb67c1e6ec421bf
Reviewed-on: https://webrtc-review.googlesource.com/58089
Commit-Queue: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Oskar Sundbom <ossu@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22259}
diff --git a/api/audio_codecs/opus/audio_encoder_opus.cc b/api/audio_codecs/opus/audio_encoder_opus.cc
index 603da6f..8ba66fb 100644
--- a/api/audio_codecs/opus/audio_encoder_opus.cc
+++ b/api/audio_codecs/opus/audio_encoder_opus.cc
@@ -31,7 +31,8 @@
 
 std::unique_ptr<AudioEncoder> AudioEncoderOpus::MakeAudioEncoder(
     const AudioEncoderOpusConfig& config,
-    int payload_type) {
+    int payload_type,
+    rtc::Optional<AudioCodecPairId> /*codec_pair_id*/) {
   return AudioEncoderOpusImpl::MakeAudioEncoder(config, payload_type);
 }