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/acm2/acm_receiver.h b/webrtc/modules/audio_coding/acm2/acm_receiver.h
index d5a644d..86fd927 100644
--- a/webrtc/modules/audio_coding/acm2/acm_receiver.h
+++ b/webrtc/modules/audio_coding/acm2/acm_receiver.h
@@ -12,6 +12,7 @@
 #define WEBRTC_MODULES_AUDIO_CODING_ACM2_ACM_RECEIVER_H_
 
 #include <map>
+#include <string>
 #include <vector>
 
 #include "webrtc/base/array_view.h"
@@ -117,7 +118,8 @@
                uint8_t payload_type,
                int channels,
                int sample_rate_hz,
-               AudioDecoder* audio_decoder);
+               AudioDecoder* audio_decoder,
+               const std::string& name);
 
   //
   // Sets a minimum delay for packet buffer. The given delay is maintained,