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.h b/api/audio_codecs/opus/audio_encoder_opus.h
index d348a17..6325269 100644
--- a/api/audio_codecs/opus/audio_encoder_opus.h
+++ b/api/audio_codecs/opus/audio_encoder_opus.h
@@ -14,6 +14,7 @@
 #include <memory>
 #include <vector>
 
+#include "api/audio_codecs/audio_codec_pair_id.h"
 #include "api/audio_codecs/audio_encoder.h"
 #include "api/audio_codecs/audio_format.h"
 #include "api/audio_codecs/opus/audio_encoder_opus_config.h"
@@ -32,8 +33,9 @@
   static void AppendSupportedEncoders(std::vector<AudioCodecSpec>* specs);
   static AudioCodecInfo QueryAudioEncoder(const AudioEncoderOpusConfig& config);
   static std::unique_ptr<AudioEncoder> MakeAudioEncoder(
-      const AudioEncoderOpusConfig&,
-      int payload_type);
+      const AudioEncoderOpusConfig& config,
+      int payload_type,
+      rtc::Optional<AudioCodecPairId> codec_pair_id = rtc::nullopt);
 };
 
 }  // namespace webrtc