Stopped using the NetEqDecoder enum internally in NetEq.

webrtc/modules/audio_coding/neteq/neteq_impl.h

 /*
  *  Copyright (c) 2012 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.
  */
 
@@ skipping 155 matching lines @@
 
   // Disables post-decode VAD.
   void DisableVad() override;
 
   rtc::Optional<uint32_t> GetPlayoutTimestamp() const override;
 
   int last_output_sample_rate_hz() const override;
 
   rtc::Optional<CodecInst> GetDecoder(int payload_type) const override;
 
-  const SdpAudioFormat* GetDecoderFormat(int payload_type) const override;
+  rtc::Optional<SdpAudioFormat> GetDecoderFormat(
+      int payload_type) const override;
 
   int SetTargetNumberOfChannels() override;
 
   int SetTargetSampleRate() override;
 
   // Returns the error code for the last occurred error. If no error has
   // occurred, 0 is returned.
   int LastError() const override;
 
   // Returns the error code last returned by a decoder (audio or comfort noise).
@@ skipping 220 matching lines @@
       AudioFrame::kVadPassive;
   std::unique_ptr<TickTimer::Stopwatch> generated_noise_stopwatch_
       GUARDED_BY(crit_sect_);
 
  private:
   RTC_DISALLOW_COPY_AND_ASSIGN(NetEqImpl);
 };
 
 }  // namespace webrtc
 #endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ_NETEQ_IMPL_H_