Stop source and fire MediaStreamTrack ended event if missing audio input callbacks are detected.

content/renderer/media/webrtc/processed_local_audio_source.cc

Index: content/renderer/media/webrtc/processed_local_audio_source.cc
diff --git a/content/renderer/media/webrtc/processed_local_audio_source.cc b/content/renderer/media/webrtc/processed_local_audio_source.cc
index 75b7d4a4b6c97d9e0ff69b0321d1562b045a15e4..6bad2e442c916dde899f69d87aeb0084a54aed59 100644
--- a/content/renderer/media/webrtc/processed_local_audio_source.cc
+++ b/content/renderer/media/webrtc/processed_local_audio_source.cc
@@ -201,12 +201,23 @@ bool ProcessedLocalAudioSource::EnsureSourceIsStarted() {
   // Register this source with the WebRtcAudioDeviceImpl.
   rtc_audio_device->AddAudioCapturer(this);
 
+  // Start detecting no callbacks.
+  base::subtle::Release_Store(&input_callback_is_active_, false);
+  last_callback_time_ = base::TimeTicks::Now();
+  check_alive_timer_.Start(
+    FROM_HERE, base::TimeDelta::FromSeconds(5),
+    this, &ProcessedLocalAudioSource::CheckIfInputStreamIsAlive);
+  DCHECK(check_alive_timer_.IsRunning());
+
   return true;
 }
 
 void ProcessedLocalAudioSource::EnsureSourceIsStopped() {
   DCHECK(thread_checker_.CalledOnValidThread());
 
+  check_alive_timer_.Stop();
+  DCHECK(!check_alive_timer_.IsRunning());
+
   scoped_refptr<media::AudioCapturerSource> source_to_stop;
   {
     base::AutoLock auto_lock(source_lock_);
@@ -267,6 +278,10 @@ void ProcessedLocalAudioSource::Capture(const media::AudioBus* audio_bus,
                                         int audio_delay_milliseconds,
                                         double volume,
                                         bool key_pressed) {
+  base::subtle::Release_Store(&input_callback_is_active_, true);

[ossu-chromium, 2017/05/18 13:38:54]

Perhaps just store last_callback_time_ atomically? Don't think tracking activity
with a bool as well adds any functionality.

[Henrik Grunell, 2017/05/19 06:00:00]

Yeah, this is going away. The CL is not ready for review yet. :)

+  // TODO: Post task.
+  last_callback_time_ = base::TimeTicks::Now();
+
 #if defined(OS_WIN) || defined(OS_MACOSX)
   DCHECK_LE(volume, 1.0);
 #elif (defined(OS_LINUX) && !defined(OS_CHROMEOS)) || defined(OS_OPENBSD)
@@ -373,4 +388,17 @@ int ProcessedLocalAudioSource::GetBufferSize(int sample_rate) const {
   return (sample_rate / 100);
 }
 
+void ProcessedLocalAudioSource::CheckIfInputStreamIsAlive() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+//  bool active = base::subtle::Acquire_Load(&input_callback_is_active_);
+  base::TimeDelta time_since_last_callback =
+      base::TimeTicks::Now() - last_callback_time_;
+  if (time_since_last_callback > base::TimeDelta::FromSeconds(5)) {
+//  if (!active) {
+    LOG(ERROR) << "********** Detected missing callbacks. Stopping.";
+    StopSourceOnError("Detected missing callbacks.");
+  }
+}
+
 }  // namespace content