Adding stats that can be used to compute output audio levels.

webrtc/pc/rtcstats_integrationtest.cc

Index: webrtc/pc/rtcstats_integrationtest.cc
diff --git a/webrtc/pc/rtcstats_integrationtest.cc b/webrtc/pc/rtcstats_integrationtest.cc
index 03fb96c0e33a3d5c9cc2b6c6b0d211c7dc4d16e7..1793a9e70f037d211816ea81a0858cab9cdb21b7 100644
--- a/webrtc/pc/rtcstats_integrationtest.cc
+++ b/webrtc/pc/rtcstats_integrationtest.cc
@@ -473,6 +473,8 @@ class RTCStatsReportVerifier {
       verifier.TestMemberIsUndefined(media_stream_track.echo_return_loss);
       verifier.TestMemberIsUndefined(
           media_stream_track.echo_return_loss_enhancement);
+      verifier.TestMemberIsUndefined(media_stream_track.total_audio_energy);
+      verifier.TestMemberIsUndefined(media_stream_track.total_samples_duration);
     } else {
       RTC_DCHECK_EQ(*media_stream_track.kind,
                     RTCMediaStreamTrackKind::kAudio);
@@ -489,6 +491,20 @@ class RTCStatsReportVerifier {
       verifier.TestMemberIsUndefined(media_stream_track.full_frames_lost);
       // Audio-only members
       verifier.TestMemberIsNonNegative<double>(media_stream_track.audio_level);
+      // Remote audio tracks are expected to have audio energy/duration values
+      // that can be used to compute audio levels between getStats calls.
+      // TODO(deadbeef): Implement for sent audio tracks as well.
+      if (media_stream_track.remote_source.is_defined() &&
+          *media_stream_track.remote_source) {
+        verifier.TestMemberIsNonNegative<double>(
+            media_stream_track.total_audio_energy);
+        verifier.TestMemberIsNonNegative<double>(
+            media_stream_track.total_samples_duration);
+      } else {
+        verifier.TestMemberIsUndefined(media_stream_track.total_audio_energy);
+        verifier.TestMemberIsUndefined(
+            media_stream_track.total_samples_duration);
+      }
       // TODO(hbos): |echo_return_loss| and |echo_return_loss_enhancement| are
       // flaky on msan bot (sometimes defined, sometimes undefined). Should the
       // test run until available or is there a way to have it always be