Expose new audio stats on the API

Several new audio stats were recently standardized and implemented in
WebRTC in https://webrtc-review.googlesource.com/c/src/+/133887. This CL
adds these to the GetStats API.

Bug: webrtc:10442, webrtc:10443, webrtc:10444
Change-Id: I0e898ac14777e82b1a9099b5e0a5584eb9cb5934
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/134213
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Commit-Queue: Ivo Creusen <ivoc@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27839}
diff --git a/media/base/media_channel.h b/media/base/media_channel.h
index 69570e7..15721c5 100644
--- a/media/base/media_channel.h
+++ b/media/base/media_channel.h
@@ -479,9 +479,14 @@
   uint64_t total_samples_received = 0;
   double total_output_duration = 0.0;
   uint64_t concealed_samples = 0;
+  uint64_t silent_concealed_samples = 0;
   uint64_t concealment_events = 0;
   double jitter_buffer_delay_seconds = 0.0;
   uint64_t jitter_buffer_emitted_count = 0;
+  uint64_t inserted_samples_for_deceleration = 0;
+  uint64_t removed_samples_for_acceleration = 0;
+  uint64_t fec_packets_received = 0;
+  uint64_t fec_packets_discarded = 0;
   // Stats below DO NOT correspond directly to anything in the WebRTC stats
   // fraction of synthesized audio inserted through expansion.
   float expand_rate = 0.0f;