Moved codec-specific audio packet splitting into decoders.

webrtc/modules/audio_coding/codecs/pcm16b/audio_decoder_pcm16b.h

Index: webrtc/modules/audio_coding/codecs/pcm16b/audio_decoder_pcm16b.h
diff --git a/webrtc/modules/audio_coding/codecs/pcm16b/audio_decoder_pcm16b.h b/webrtc/modules/audio_coding/codecs/pcm16b/audio_decoder_pcm16b.h
index df94a6a6bdd0092a1b901572238e357de2bcedae..c1fa78d21b2c40f40dc9475f59d9b292fd88f6e7 100644
--- a/webrtc/modules/audio_coding/codecs/pcm16b/audio_decoder_pcm16b.h
+++ b/webrtc/modules/audio_coding/codecs/pcm16b/audio_decoder_pcm16b.h
@@ -20,6 +20,8 @@ class AudioDecoderPcm16B final : public AudioDecoder {
  public:
   AudioDecoderPcm16B(int sample_rate_hz, size_t num_channels);
   void Reset() override;
+  PacketSplits SplitPacket(const uint8_t* payload,
+                           size_t payload_len) const override;
   int PacketDuration(const uint8_t* encoded, size_t encoded_len) const override;
   int SampleRateHz() const override;
   size_t Channels() const override;