Convert CNG into C++ and remove it from AudioDecoder

webrtc/modules/audio_coding/neteq/payload_splitter.cc

 /*
  *  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 125 matching lines @@
       return kUnknownPayloadType;
     }
     // No splitting for a sync-packet.
     if (packet->sync_packet) {
       ++it;
       continue;
     }
 
     // Not an FEC packet.
     AudioDecoder* decoder = decoder_database->GetDecoder(payload_type);
-    // decoder should not return NULL.
-    assert(decoder != NULL);
+    // decoder should not return NULL, except for CNG as that's no longer a
+    // Decoder.

[kwiberg-webrtc, 2016/04/09 07:34:49]

Please avoid referring to how things used to be, since that'll eventually cease
to be enlightening.

  // This should either be CNG or a real decoder.
  RTC_DCHECK(decoder || decoder_database->IsComfortNoise(payload_type));

[ossu, 2016/04/11 08:31:10]

Acknowledged.

+    assert(decoder != NULL || decoder_database->IsComfortNoise(payload_type));
     if (!decoder ||
         !decoder->PacketHasFec(packet->payload, packet->payload_length)) {
       ++it;
       continue;
     }
 
     switch (info->codec_type) {
       case NetEqDecoder::kDecoderOpus:
       case NetEqDecoder::kDecoderOpus_2ch: {
         // The main payload of this packet should be decoded as a primary
@@ skipping 274 matching lines @@
     new_packet->payload = new uint8_t[bytes_per_frame];
     memcpy(new_packet->payload, payload_ptr, bytes_per_frame);
     payload_ptr += bytes_per_frame;
     new_packets->push_back(new_packet);
     len -= bytes_per_frame;
   }
   return kOK;
 }
 
 }  // namespace webrtc