Moved codec-specific audio packet splitting into decoders.

webrtc/modules/audio_coding/codecs/ilbc/audio_decoder_ilbc.h

Index: webrtc/modules/audio_coding/codecs/ilbc/audio_decoder_ilbc.h
diff --git a/webrtc/modules/audio_coding/codecs/ilbc/audio_decoder_ilbc.h b/webrtc/modules/audio_coding/codecs/ilbc/audio_decoder_ilbc.h
index 1083479ad864594ea88807f209aeec44fa3502c9..88dc1588aee7a2a0b4d5ae1f8a1c733137e21c8a 100644
--- a/webrtc/modules/audio_coding/codecs/ilbc/audio_decoder_ilbc.h
+++ b/webrtc/modules/audio_coding/codecs/ilbc/audio_decoder_ilbc.h
@@ -25,6 +25,8 @@ class AudioDecoderIlbc final : public AudioDecoder {
   bool HasDecodePlc() const override;
   size_t DecodePlc(size_t num_frames, int16_t* decoded) override;
   void Reset() override;
+  PacketSplits SplitPacket(const uint8_t* payload,
+                           size_t payload_len) const override;
   int SampleRateHz() const override;
   size_t Channels() const override;