Update interfaces/webrtc-stats.idl (#17532)

Source: https://github.com/tidoust/reffy-reports/blob/b3787dc/whatwg/idl/webrtc-stats.idl
Build: https://travis-ci.org/tidoust/reffy-reports/builds/550916945
diff --git a/interfaces/webrtc-stats.idl b/interfaces/webrtc-stats.idl
index 981317f..f29e00d 100644
--- a/interfaces/webrtc-stats.idl
+++ b/interfaces/webrtc-stats.idl
@@ -69,7 +69,9 @@
              DOMString receiverId;
              DOMString remoteId;
              unsigned long framesDecoded;
+             unsigned long keyFramesDecoded;
              unsigned long long qpSum;
+             double totalDecodeTime;
              DOMHighResTimeStamp lastPacketReceivedTimestamp;
              double averageRtcpInterval;
              unsigned long fecPacketsReceived;
@@ -109,6 +111,7 @@
              double targetBitrate;
              unsigned long long totalEncodedBytesTarget;
              unsigned long framesEncoded;
+             unsigned long keyFramesEncoded;
              unsigned long long qpSum;
              double totalEncodeTime;
              double totalPacketSendDelay;
@@ -187,7 +190,6 @@
              unsigned long framesCaptured;
              unsigned long framesSent;
              unsigned long hugeFramesSent;
-             unsigned long keyFramesSent;
 };
 
 dictionary RTCSenderVideoTrackAttachmentStats : RTCVideoSenderStats {
@@ -198,7 +200,6 @@
              double jitterBufferDelay;
              unsigned long long jitterBufferEmittedCount;
              unsigned long framesReceived;
-             unsigned long keyFramesReceived;
              unsigned long framesDecoded;
              unsigned long framesDropped;
              unsigned long partialFramesLost;
@@ -359,3 +360,11 @@
 partial dictionary RTCInboundRtpStreamStats {
           double fractionLost;
 };
+
+partial dictionary RTCVideoSenderStats {
+          unsigned long keyFramesSent;
+};
+
+partial dictionary RTCVideoReceiverStats {
+          unsigned long keyFramesReceived;
+};