Ensures that AudioDeviceBuffer::StopPeriodicLogging works as intended

webrtc/modules/audio_device/audio_device_buffer.h

 /*
  *  Copyright (c) 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 216 matching lines @@
   int16_t rec_stat_count_ ACCESS_ON(recording_thread_checker_);
   int16_t play_stat_count_ ACCESS_ON(playout_thread_checker_);
 
   // Time stamps of when playout and recording starts.
   uint64_t play_start_time_ ACCESS_ON(main_thread_checker_);
   uint64_t rec_start_time_ ACCESS_ON(main_thread_checker_);
 
   // Set to true at construction and modified to false as soon as one audio-
   // level estimate larger than zero is detected.
   bool only_silence_recorded_;
+
+  // Set to true when logging of audio stats is enabled for the first time in
+  // StartPeriodicLogging() and set to false by StopPeriodicLogging().
+  // Setting this member to false prevents (possiby invalid) log messages from
+  // being printed in the LogStats() task.
+  bool log_stats_ ACCESS_ON(task_queue_);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_DEVICE_AUDIO_DEVICE_BUFFER_H_