RTCOutboundRTPStreamStats.roundTripTime: Only report non-negative values.

webrtc/api/rtcstats_integrationtest.cc

Index: webrtc/api/rtcstats_integrationtest.cc
diff --git a/webrtc/api/rtcstats_integrationtest.cc b/webrtc/api/rtcstats_integrationtest.cc
index 923997cb452b2463a35cc03014c01949d4d90060..0f60377eb221b39c626ea2624bcfa33c3a2e5b93 100644
--- a/webrtc/api/rtcstats_integrationtest.cc
+++ b/webrtc/api/rtcstats_integrationtest.cc
@@ -497,7 +497,8 @@ class RTCStatsReportVerifier {
     verifier.TestMemberIsDefined(outbound_stream.packets_sent);
     verifier.TestMemberIsDefined(outbound_stream.bytes_sent);
     verifier.TestMemberIsUndefined(outbound_stream.target_bitrate);
-    verifier.TestMemberIsDefined(outbound_stream.round_trip_time);
+    // TODO(hbos): Defined in video but not audio case. Why? crbug.com/669877
+    verifier.MarkMemberTested(outbound_stream.round_trip_time, true);
     return verifier.ExpectAllMembersSuccessfullyTested();
   }