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

content/renderer/media/webrtc/processed_local_audio_source.cc

 // Copyright (c) 2012 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 "content/renderer/media/webrtc/processed_local_audio_source.h"
 
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/stringprintf.h"
 #include "content/renderer/media/audio_device_factory.h"
@@ skipping 183 matching lines @@
   new_source->SetAutomaticGainControl(true);
   {
     base::AutoLock auto_lock(source_lock_);
     source_ = std::move(new_source);
   }
   source_->Start();
 
   // 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_);
     if (!source_)
       return;
     source_to_stop = std::move(source_);
   }
 
   if (WebRtcAudioDeviceImpl* rtc_audio_device =
       pc_factory_->GetWebRtcAudioDevice()) {
@@ skipping 40 matching lines @@
 }
 
 void ProcessedLocalAudioSource::OnCaptureStarted() {
   started_callback_.Run(this, MEDIA_DEVICE_OK, "");
 }
 
 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)
   // We have a special situation on Linux where the microphone volume can be
   // "higher than maximum". The input volume slider in the sound preference
   // allows the user to set a scaling that is higher than 100%. It means that
   // even if the reported maximum levels is N, the actual microphone level can
   // go up to 1.5x*N and that corresponds to a normalized |volume| of 1.5x.
   DCHECK_LE(volume, 1.6);
 #endif
@@ skipping 86 matching lines @@
     return hardware_buffer_size;
 
   // If the buffer size is missing from the StreamDeviceInfo, provide 10ms as a
   // fall-back.
   //
   // TODO(miu): Identify where/why the buffer size might be missing, fix the
   // code, and then require it here. http://crbug.com/638081
   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