Bug 1556766 - Add telemetry for WebRTC video codecs used in calls; r=chutten,drno

This adds a scalar for the codecs used when receiving and sending video in
a WebRTC call.

Differential Revision: https://phabricator.services.mozilla.com/D33840

--HG--
extra : moz-landing-system : lando

media/webrtc/signaling/src/media-conduit/VideoConduit.cpp

@@ -612,6 +612,12 @@ MediaConduitErrorCode WebrtcVideoConduit::CreateSendStream() {
   MOZ_ASSERT(NS_IsMainThread());
   mMutex.AssertCurrentThreadOwns();
 
+  nsAutoString codecName;
+  codecName.AssignASCII(
+      mSendStreamConfig.encoder_settings.payload_name.c_str());
+  Telemetry::ScalarAdd(Telemetry::ScalarID::WEBRTC_VIDEO_SEND_CODEC_USED,
+                       codecName, 1);
+
   webrtc::VideoCodecType encoder_type =
       SupportedCodecType(webrtc::PayloadStringToCodecType(
           mSendStreamConfig.encoder_settings.payload_name));
@@ -667,6 +673,11 @@ MediaConduitErrorCode WebrtcVideoConduit::CreateRecvStream() {
 
   mRecvStreamConfig.decoders.clear();
   for (auto& config : mRecvCodecList) {
+    nsAutoString codecName;
+    codecName.AssignASCII(config->mName.c_str());
+    Telemetry::ScalarAdd(Telemetry::ScalarID::WEBRTC_VIDEO_RECV_CODEC_USED,
+                         codecName, 1);
+
     decoder_type =
         SupportedCodecType(webrtc::PayloadStringToCodecType(config->mName));
     if (decoder_type == webrtc::VideoCodecType::kVideoCodecUnknown) {

toolkit/components/telemetry/Scalars.yaml

@@ -935,6 +935,37 @@ webrtc.nicer:
       - 'main'
       - 'content'
 
+webrtc.video:
+  recv_codec_used:
+    bug_numbers:
+      - 1556766
+    description: >
+      The video codec used for receiving video on a WebRTC call.
+    expires: "never"
+    kind: uint
+    keyed: true
+    notification_emails:
+      - dminor@mozilla.com
+      - nohlmeier@mozilla.com
+    release_channel_collection: opt-out
+    record_in_processes:
+      - 'content'
+
+  send_codec_used:
+    bug_numbers:
+      - 1556766
+    description: >
+      The video codec used for sending video on a WebRTC call.
+    expires: "never"
+    kind: uint
+    keyed: true
+    notification_emails:
+      - dminor@mozilla.com
+      - nohlmeier@mozilla.com
+    release_channel_collection: opt-out
+    record_in_processes:
+      - 'content'
+
 webrtc.sdp:
   parser_diff:
     bug_numbers: