getStats: add relayProtocol

adds relayProtocol stats member.

BUG=webrtc:7063

Change-Id: Iedef61506cac1ab2e3e38c836881748965eeda3d
Reviewed-on: https://webrtc-review.googlesource.com/97780
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Commit-Queue: Philipp Hancke <philipp.hancke@googlemail.com>
Cr-Commit-Position: refs/heads/master@{#24923}
diff --git a/api/stats/rtcstats_objects.h b/api/stats/rtcstats_objects.h
index a597d6f..f377809 100644
--- a/api/stats/rtcstats_objects.h
+++ b/api/stats/rtcstats_objects.h
@@ -199,6 +199,7 @@
   RTCStatsMember<std::string> ip;
   RTCStatsMember<int32_t> port;
   RTCStatsMember<std::string> protocol;
+  RTCStatsMember<std::string> relay_protocol;
   // TODO(hbos): Support enum types? "RTCStatsMember<RTCIceCandidateType>"?
   RTCStatsMember<std::string> candidate_type;
   RTCStatsMember<int32_t> priority;