Make an enum class out of NetEqDecoder, and hide the neteq_decoders_ table

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 92 matching lines @@
   // The speech type is written to |type|, if |type| is not NULL.
   // Returns kOK on success, or kFail in case of an error.
   int GetAudio(size_t max_length,
                int16_t* output_audio,
                size_t* samples_per_channel,
                int* num_channels,
                NetEqOutputType* type) override;
 
   // Associates |rtp_payload_type| with |codec| and stores the information in
   // the codec database. Returns kOK on success, kFail on failure.
-  int RegisterPayloadType(enum NetEqDecoder codec,
+  int RegisterPayloadType(NetEqDecoder codec,
                           uint8_t rtp_payload_type) override;
 
   // Provides an externally created decoder object |decoder| to insert in the
   // decoder database. The decoder implements a decoder of type |codec| and
   // associates it with |rtp_payload_type|. The decoder will produce samples
   // at the rate |sample_rate_hz|. Returns kOK on success, kFail on failure.
   int RegisterExternalDecoder(AudioDecoder* decoder,
-                              enum NetEqDecoder codec,
+                              NetEqDecoder codec,
                               uint8_t rtp_payload_type,
                               int sample_rate_hz) override;
 
   // Removes |rtp_payload_type| from the codec database. Returns 0 on success,
   // -1 on failure.
   int RemovePayloadType(uint8_t rtp_payload_type) override;
 
   bool SetMinimumDelay(int delay_ms) override;
 
   bool SetMaximumDelay(int delay_ms) override;
@@ skipping 271 matching lines @@
   // module is designed to compensate for this.
   int decoded_packet_sequence_number_ GUARDED_BY(crit_sect_);
   uint32_t decoded_packet_timestamp_ GUARDED_BY(crit_sect_);
 
  private:
   RTC_DISALLOW_COPY_AND_ASSIGN(NetEqImpl);
 };
 
 }  // namespace webrtc
 #endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ_NETEQ_IMPL_H_