Report video and network stats averaged over 1s, and create corresponding UMA metrics.

remoting/client/chromoting_stats.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // ChromotingStats defines a bundle of performance counters and statistics
 // for chromoting.
 
 #ifndef REMOTING_CLIENT_CHROMOTING_STATS_H_
 #define REMOTING_CLIENT_CHROMOTING_STATS_H_
 
 #include "remoting/base/rate_counter.h"
 #include "remoting/base/running_average.h"
 
 namespace remoting {
 
 class ChromotingStats {
  public:
   ChromotingStats();
   virtual ~ChromotingStats();
 
+  // Constant used to calculate the average for rate metrics and used by the
+  // plugin for the frequency at which stats should be updated.
+  static const int kStatsUpdateFrequencyInSeconds = 1;
+
+  // The video and packet rate metrics below are updated per video packet
+  // received and then, for reporting, averaged over a 1s time-window.
+  // Bytes per second for non-empty video-packets.
   RateCounter* video_bandwidth() { return &video_bandwidth_; }
+
+  // Frames per second for non-empty video-packets.
   RateCounter* video_frame_rate() { return &video_frame_rate_; }
+
+  // Video packets per second, including empty video-packets.
+  // This will be greater than the frame rate, as individual frames are
+  // contained in packets, some of which might be empty (e.g. when there are no
+  // screen changes).
+  RateCounter* video_packet_rate() { return &video_packet_rate_; }
+
+  // The latency metrics below are recorded per video packet received and, for
+  // reporting, averaged over the N most recent samples.
+  // N is defined by kLatencySampleSize.
   RunningAverage* video_capture_ms() { return &video_capture_ms_; }
   RunningAverage* video_encode_ms() { return &video_encode_ms_; }
   RunningAverage* video_decode_ms() { return &video_decode_ms_; }
   RunningAverage* video_paint_ms() { return &video_paint_ms_; }
   RunningAverage* round_trip_ms() { return &round_trip_ms_; }
 
  private:
   RateCounter video_bandwidth_;
   RateCounter video_frame_rate_;
+  RateCounter video_packet_rate_;
   RunningAverage video_capture_ms_;
   RunningAverage video_encode_ms_;
   RunningAverage video_decode_ms_;
   RunningAverage video_paint_ms_;
   RunningAverage round_trip_ms_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromotingStats);
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_CLIENT_CHROMOTING_STATS_H_