Fix UMA metrics for MediaSourcePlayer.

media/base/android/media_statistics.cc

 // Copyright 2015 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.
 
 #include "media/base/android/media_statistics.h"
 
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
 #include "media/base/android/demuxer_stream_player_params.h"
 
@@ skipping 35 matching lines @@
     start_time_ = current_playback_time;
   }
 }
 
 void MediaStatistics::StopAndReport(base::TimeDelta current_playback_time) {
   DVLOG(1) << __FUNCTION__;
 
   if (start_time_ == kNoTimestamp())
     return;  // skip if there was no prior Start().
 
+  if (current_playback_time == kNoTimestamp()) {
+    // Cancel the start event and skip if current time is unknown.
+    start_time_ = kNoTimestamp();
+    return;
+  }
+
   base::TimeDelta duration = current_playback_time - start_time_;
 
   // Reset start time.
   start_time_ = kNoTimestamp();
 
   if (duration < base::TimeDelta::FromSeconds(kMinDurationInSeconds))
     return;  // duration is too short.
 
   if (duration > base::TimeDelta::FromSeconds(kMaxDurationInSeconds))
     return;  // duration is too long.
@@ skipping 44 matching lines @@
 
   uint32_t total_frames = audio_frame_stats_.total ? audio_frame_stats_.total
                                                    : video_frame_stats_.total;
   if (total_frames) {
     UMA_HISTOGRAM_COUNTS("Media.MSE.Starvations",
                          kOneMillion * num_starvations_ / total_frames);
   }
 }
 
 }  // namespace media