AudioDecoder: New method SampleRateHz, + implementations for our codecs

webrtc/modules/audio_coding/codecs/g722/audio_decoder_g722.h

 /*
  *  Copyright (c) 2015 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_G722_AUDIO_DECODER_G722_H_
 #define WEBRTC_MODULES_AUDIO_CODING_CODECS_G722_AUDIO_DECODER_G722_H_
 
 #include "webrtc/base/constructormagic.h"
 #include "webrtc/modules/audio_coding/codecs/audio_decoder.h"
 
 typedef struct WebRtcG722DecInst G722DecInst;
 
 namespace webrtc {
 
 class AudioDecoderG722 final : public AudioDecoder {
  public:
   AudioDecoderG722();
   ~AudioDecoderG722() override;
   bool HasDecodePlc() const override;
   void Reset() override;
   int PacketDuration(const uint8_t* encoded, size_t encoded_len) const override;
+  int SampleRateHz() const override;
   size_t Channels() const override;
 
  protected:
   int DecodeInternal(const uint8_t* encoded,
                      size_t encoded_len,
                      int sample_rate_hz,
                      int16_t* decoded,
                      SpeechType* speech_type) override;
 
  private:
   G722DecInst* dec_state_;
   RTC_DISALLOW_COPY_AND_ASSIGN(AudioDecoderG722);
 };
 
 class AudioDecoderG722Stereo final : public AudioDecoder {
  public:
   AudioDecoderG722Stereo();
   ~AudioDecoderG722Stereo() override;
   void Reset() override;
+  int SampleRateHz() const override;
+  size_t Channels() const override;
 
  protected:
   int DecodeInternal(const uint8_t* encoded,
                      size_t encoded_len,
                      int sample_rate_hz,
                      int16_t* decoded,
                      SpeechType* speech_type) override;
-  size_t Channels() const override;
 
  private:
   // Splits the stereo-interleaved payload in |encoded| into separate payloads
   // for left and right channels. The separated payloads are written to
   // |encoded_deinterleaved|, which must hold at least |encoded_len| samples.
   // The left channel starts at offset 0, while the right channel starts at
   // offset encoded_len / 2 into |encoded_deinterleaved|.
   void SplitStereoPacket(const uint8_t* encoded,
                          size_t encoded_len,
                          uint8_t* encoded_deinterleaved);
 
   G722DecInst* dec_state_left_;
   G722DecInst* dec_state_right_;
   RTC_DISALLOW_COPY_AND_ASSIGN(AudioDecoderG722Stereo);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_CODING_CODECS_G722_AUDIO_DECODER_G722_H_