Ensures that AudioDeviceBuffer::StopPeriodicLogging works as intended

webrtc/modules/audio_device/audio_device_buffer.h

Index: webrtc/modules/audio_device/audio_device_buffer.h
diff --git a/webrtc/modules/audio_device/audio_device_buffer.h b/webrtc/modules/audio_device/audio_device_buffer.h
index 0e7a22dda5d9f51e08e50bfe474548df56d0e782..167ebd234afcd3a46524a8c38cd4456e296c7db1 100644
--- a/webrtc/modules/audio_device/audio_device_buffer.h
+++ b/webrtc/modules/audio_device/audio_device_buffer.h
@@ -234,6 +234,12 @@ class AudioDeviceBuffer {
   // 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