Expose `jitterBufferEmittedCount` in addition to the existing `jitterBufferDelay` for `getStats()`.

NetEq currently only passes `jitterBufferDelay` to `getStats()`. We need its paired `jitterBufferEmittedCount` denominator stat for the calculations to be accurate.

Bug: webrtc:10192
Change-Id: I655aea629026ce9101409c2e0f18c2fa57a1c3ab
Reviewed-on: https://webrtc-review.googlesource.com/c/117320
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Henrik Lundin <henrik.lundin@webrtc.org>
Commit-Queue: Chen Xing <chxg@google.com>
Cr-Commit-Position: refs/heads/master@{#26276}
diff --git a/api/stats/rtcstats_objects.h b/api/stats/rtcstats_objects.h
index e69bc8e..b27bf73 100644
--- a/api/stats/rtcstats_objects.h
+++ b/api/stats/rtcstats_objects.h
@@ -284,6 +284,7 @@
   // implemented for audio only).
   // https://crbug.com/webrtc/8318
   RTCStatsMember<double> jitter_buffer_delay;
+  RTCStatsMember<uint64_t> jitter_buffer_emitted_count;
   // Video-only members
   RTCStatsMember<uint32_t> frame_width;
   RTCStatsMember<uint32_t> frame_height;