Adding cbr support for Opus

webrtc/modules/audio_coding/codecs/cng/audio_encoder_cng.h

 /*
  *  Copyright (c) 2014 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 40 matching lines @@
   size_t NumChannels() const override;
   int RtpTimestampRateHz() const override;
   size_t Num10MsFramesInNextPacket() const override;
   size_t Max10MsFramesInAPacket() const override;
   int GetTargetBitrate() const override;
   EncodedInfo EncodeImpl(uint32_t rtp_timestamp,
                          rtc::ArrayView<const int16_t> audio,
                          rtc::Buffer* encoded) override;
   void Reset() override;
   bool SetFec(bool enable) override;
+  bool SetCbr(bool enable) override;
   bool SetDtx(bool enable) override;
   bool SetApplication(Application application) override;
   void SetMaxPlaybackRate(int frequency_hz) override;
   rtc::ArrayView<std::unique_ptr<AudioEncoder>> ReclaimContainedEncoders()
       override;
   void OnReceivedUplinkPacketLossFraction(
       float uplink_packet_loss_fraction) override;
   void OnReceivedUplinkBandwidth(
       int target_audio_bitrate_bps,
       rtc::Optional<int64_t> probing_interval_ms) override;
@@ skipping 14 matching lines @@
   bool last_frame_active_;
   std::unique_ptr<Vad> vad_;
   std::unique_ptr<ComfortNoiseEncoder> cng_encoder_;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(AudioEncoderCng);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_CODING_CODECS_CNG_AUDIO_ENCODER_CNG_H_