RTCMediaStreamTrackStats.ssrcIds collected by RTCStatsCollector.

webrtc/api/rtcstatscollector.h

 /*
  *  Copyright 2016 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 138 matching lines @@
   rtc::Thread* const signaling_thread_;
   rtc::Thread* const worker_thread_;
   rtc::Thread* const network_thread_;
   rtc::AsyncInvoker invoker_;
 
   int num_pending_partial_reports_;
   int64_t partial_report_timestamp_us_;
   rtc::scoped_refptr<RTCStatsReport> partial_report_;
   std::vector<rtc::scoped_refptr<RTCStatsCollectorCallback>> callbacks_;
 
-  // Set in |GetStatsReport|, used in |ProducePartialResultsOnNetworkThread|
+  // Set in |GetStatsReport|, read in |ProducePartialResultsOnNetworkThread|
   // (not passed as arguments to avoid copies). This is thread safe - it is set
   // at the start of |GetStatsReport| after making sure there are no pending
   // stats requests in progress.
   std::unique_ptr<ChannelNamePairs> channel_name_pairs_;
+  // ... Also read in |ProducePartialResultsOnSignalingThread|.

[hta-webrtc, 2017/01/02 15:29:46]

It's easier to read these comment-above-declaration comments if you start off
with saying what it is, like this:

// Information about the media.
// Read in |ProducePartialResultsOnSignalingThread|.

This comment isn't clear about which parts of the previous comment (if any)
apply to this variable.

   std::unique_ptr<MediaInfo> media_info_;
 
   // A timestamp, in microseconds, that is based on a timer that is
   // monotonically increasing. That is, even if the system clock is modified the
   // difference between the timer and this timestamp is how fresh the cached
   // report is.
   int64_t cache_timestamp_us_;
   int64_t cache_lifetime_us_;
   rtc::scoped_refptr<const RTCStatsReport> cached_report_;
 
@@ skipping 18 matching lines @@
 };
 
 const char* CandidateTypeToRTCIceCandidateTypeForTesting(
     const std::string& type);
 const char* DataStateToRTCDataChannelStateForTesting(
     DataChannelInterface::DataState state);
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_API_RTCSTATSCOLLECTOR_H_