NetEq: Add codec name and RTP timestamp rate to DecoderInfo

The new fields are default-populated for built-in decoders, but for
external decoders, the name can now be given when registering the
decoder.

BUG=webrtc:3520

Review URL: https://codereview.webrtc.org/1484343003

Cr-Commit-Position: refs/heads/master@{#10952}
diff --git a/webrtc/modules/audio_coding/neteq/include/neteq.h b/webrtc/modules/audio_coding/neteq/include/neteq.h
index 88677d8..abe09a3 100644
--- a/webrtc/modules/audio_coding/neteq/include/neteq.h
+++ b/webrtc/modules/audio_coding/neteq/include/neteq.h
@@ -174,17 +174,24 @@
                        size_t* samples_per_channel, int* num_channels,
                        NetEqOutputType* type) = 0;
 
-  // Associates |rtp_payload_type| with |codec| and stores the information in
-  // the codec database. Returns 0 on success, -1 on failure.
+  // Associates |rtp_payload_type| with |codec| and |codec_name|, and stores the
+  // information in the codec database. Returns 0 on success, -1 on failure.
+  // The name is only used to provide information back to the caller about the
+  // decoders. Hence, the name is arbitrary, and may be empty.
   virtual int RegisterPayloadType(NetEqDecoder codec,
+                                  const std::string& codec_name,
                                   uint8_t rtp_payload_type) = 0;
 
   // Provides an externally created decoder object |decoder| to insert in the
   // decoder database. The decoder implements a decoder of type |codec| and
-  // associates it with |rtp_payload_type|. The decoder will produce samples
-  // at the rate |sample_rate_hz|. Returns kOK on success, kFail on failure.
+  // associates it with |rtp_payload_type| and |codec_name|. The decoder will
+  // produce samples at the rate |sample_rate_hz|. Returns kOK on success, kFail
+  // on failure.
+  // The name is only used to provide information back to the caller about the
+  // decoders. Hence, the name is arbitrary, and may be empty.
   virtual int RegisterExternalDecoder(AudioDecoder* decoder,
                                       NetEqDecoder codec,
+                                      const std::string& codec_name,
                                       uint8_t rtp_payload_type,
                                       int sample_rate_hz) = 0;