Pass SdpAudioFormat through Channel, without converting to CodecInst

webrtc/modules/audio_coding/codecs/audio_decoder_factory.h

 /*
  *  Copyright (c) 2016 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.
  */
 
 #ifndef WEBRTC_MODULES_AUDIO_CODING_CODECS_AUDIO_DECODER_FACTORY_H_
 #define WEBRTC_MODULES_AUDIO_CODING_CODECS_AUDIO_DECODER_FACTORY_H_
 
 #include <memory>
 #include <vector>
 
 #include "webrtc/base/atomicops.h"
 #include "webrtc/base/refcount.h"
 #include "webrtc/modules/audio_coding/codecs/audio_decoder.h"
 #include "webrtc/modules/audio_coding/codecs/audio_format.h"
 
 namespace webrtc {
 
 // A factory that creates AudioDecoders.
 // NOTE: This class is still under development and may change without notice.
 class AudioDecoderFactory : public rtc::RefCountInterface {
  public:
   virtual std::vector<AudioCodecSpec> GetSupportedDecoders() = 0;
 
+  virtual bool IsSupportedDecoder(const SdpAudioFormat& format) = 0;
+
   virtual std::unique_ptr<AudioDecoder> MakeAudioDecoder(
       const SdpAudioFormat& format) = 0;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_CODING_CODECS_AUDIO_DECODER_FACTORY_H_