Reland "Piping audio interruption metrics to API layer"

The metrics are now added as RTCNonStandardStatsMember objects in
RTCMediaStreamTrackStats. Unit tests are updated.

This is a reland of https://webrtc-review.googlesource.com/c/src/+/134303,
with fixes.

TBR=kwiberg@webrtc.org

Bug: webrtc:10549
Change-Id: I29dcc6fbfc69156715664e71acfa054c1b2d9038
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/134500
Commit-Queue: Henrik Lundin <henrik.lundin@webrtc.org>
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Reviewed-by: Ivo Creusen <ivoc@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27806}
diff --git a/modules/audio_coding/acm2/acm_receiver.cc b/modules/audio_coding/acm2/acm_receiver.cc
index da7d621..c10a71c 100644
--- a/modules/audio_coding/acm2/acm_receiver.cc
+++ b/modules/audio_coding/acm2/acm_receiver.cc
@@ -259,6 +259,9 @@
       neteq_lifetime_stat.delayed_packet_outage_samples;
   acm_stat->relativePacketArrivalDelayMs =
       neteq_lifetime_stat.relative_packet_arrival_delay_ms;
+  acm_stat->interruptionCount = neteq_lifetime_stat.interruption_count;
+  acm_stat->totalInterruptionDurationMs =
+      neteq_lifetime_stat.total_interruption_duration_ms;
 
   NetEqOperationsAndState neteq_operations_and_state =
       neteq_->GetOperationsAndState();