Report timing frames info in GetStats.

webrtc/pc/statscollector.cc

 /*
  *  Copyright 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 231 matching lines @@
     { StatsReport::kStatsValueNamePacketsReceived, info.packets_rcvd },
     { StatsReport::kStatsValueNamePlisSent, info.plis_sent },
     { StatsReport::kStatsValueNameRenderDelayMs, info.render_delay_ms },
     { StatsReport::kStatsValueNameTargetDelayMs, info.target_delay_ms },
     { StatsReport::kStatsValueNameFramesDecoded, info.frames_decoded },
   };
 
   for (const auto& i : ints)
     report->AddInt(i.name, i.value);
   report->AddString(StatsReport::kStatsValueNameMediaType, "video");
+  report->AddString(StatsReport::kStatsValueNameTimingFrameInfo,
+                    info.timing_frame_info.ToString());

[hbos, 2017/06/27 14:08:31]

Do not add this stat if timing_frame_info is undefined.

Does this have to rely on "since last GetStats()"? Applications may call
GetStats() in multiple places (have multiple "stats consumers"). This will make
GetStats() break for >1 stats consumer unless each consumer is aware of when the
last call was and what the result of that call was. Can this be avoided?

[ilnik, 2017/06/27 15:23:56]

Multiple stats consumers do not break anything. The purpose of this stat is to
return some single timing frame info. "Since last GetStats " restriction just
makes reports as fine grained as possible. We could return latest available
info, but it is not so interesting as most delayed frame.

 }
 
 void ExtractStats(const cricket::VideoSenderInfo& info, StatsReport* report) {
   ExtractCommonSendProperties(info, report);
 
   report->AddString(StatsReport::kStatsValueNameCodecImplementationName,
                     info.encoder_implementation_name);
   report->AddBoolean(StatsReport::kStatsValueNameBandwidthLimitedResolution,
                      (info.adapt_reason & 0x2) > 0);
   report->AddBoolean(StatsReport::kStatsValueNameCpuLimitedResolution,
@@ skipping 741 matching lines @@
     StatsReport* report = entry.second;
     report->set_timestamp(stats_gathering_started_);
   }
 }
 
 void StatsCollector::ClearUpdateStatsCacheForTest() {
   stats_gathering_started_ = 0;
 }
 
 }  // namespace webrtc