Audio codec usage statistics

webrtc/modules/audio_coding/codecs/audio_encoder.h

Index: webrtc/modules/audio_coding/codecs/audio_encoder.h
diff --git a/webrtc/modules/audio_coding/codecs/audio_encoder.h b/webrtc/modules/audio_coding/codecs/audio_encoder.h
index a0f1839e73393c4ad017c6d6d5393a740187f64d..914352dc046a77d1223f1f2fccd70bd51b602f12 100644
--- a/webrtc/modules/audio_coding/codecs/audio_encoder.h
+++ b/webrtc/modules/audio_coding/codecs/audio_encoder.h
@@ -25,12 +25,30 @@ namespace webrtc {
 // type must have an implementation of this class.
 class AudioEncoder {
  public:
+  // Used for UMA logging of codec usage.

[ossu, 2016/05/12 15:18:46]

I think you should mention that they must match whatever mapping is done in this
XML file I've been hearing so much about, so people know where to look if they
need to add/change these.

[aleloi, 2016/05/12 15:30:14]

Acknowledged.

+  enum class CodecType {
+    // kOther stands for no name, other or unknown codec
+    kOther = 0,
+    kOpus,
+    kIsac,
+    kPcmA,
+    kPcmU,
+    kG722,
+    kIlbc,
+
+    // Number of histogram bins in the UMA logging of codec types. The
+    // total number of different codecs that are logged cannot exceed this
+    // numbers.

[ossu, 2016/05/12 15:18:46]

number (remove the s)

[aleloi, 2016/05/12 15:30:14]

Acknowledged.

+    kMaxLoggedAudioCodecNames = 64
+  };
+
   struct EncodedInfoLeaf {
     size_t encoded_bytes = 0;
     uint32_t encoded_timestamp = 0;
     int payload_type = 0;
     bool send_even_if_empty = false;
     bool speech = true;
+    CodecType encoder_type = CodecType::kOther;
   };
 
   // This is the main struct for auxiliary encoding information. Each encoded