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

media/audio/audio_input_device.cc

Index: media/audio/audio_input_device.cc
diff --git a/media/audio/audio_input_device.cc b/media/audio/audio_input_device.cc
index 3b83deb10e3475b9aee2c1415b73a0e00e7f718a..bbefb2f92b5b8b109bca3e567826618fe610abee 100644
--- a/media/audio/audio_input_device.cc
+++ b/media/audio/audio_input_device.cc
@@ -8,7 +8,9 @@
 #include <utility>
 
 #include "base/bind.h"
+#include "base/callback_forward.h"
 #include "base/macros.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/strings/stringprintf.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/time/time.h"
@@ -18,11 +20,29 @@
 
 namespace media {
 
+namespace {
+
 // The number of shared memory buffer segments indicated to browser process
 // in order to avoid data overwriting. This number can be any positive number,
 // dependent how fast the renderer process can pick up captured data from
 // shared memory.
-static const int kRequestedSharedMemoryCount = 10;
+const int kRequestedSharedMemoryCount = 10;
+
+// The number of seconds with missing callbacks before we report a capture
+// error. The value is based on that the Mac audio implementation can defer
+// start for 5 seconds when resuming after standby, and has a startup success
+// check 5 seconds after actually starting, where stats is logged. We must allow
+// enough time for this. See AUAudioInputStream::CheckInputStartupSuccess().
+const int kMissingCallbacksTimeBeforeErrorSeconds = 12;
+
+// The interval for checking missing callbacks.
+const int kCheckMissingCallbacksIntervalSeconds = 5;
+
+// How often AudioInputDevice::AudioThreadCallback informs that it has gotten
+// data from the source.
+const int kGotDataCallbackIntervalSeconds = 1;
+
+}  // namespace
 
 // Takes care of invoking the capture callback on the audio thread.
 // An instance of this class is created for each capture stream in
@@ -34,7 +54,8 @@ class AudioInputDevice::AudioThreadCallback
                       base::SharedMemoryHandle memory,
                       int memory_length,
                       int total_segments,
-                      CaptureCallback* capture_callback);
+                      CaptureCallback* capture_callback,
+                      base::RepeatingClosure got_data_callback);
   ~AudioThreadCallback() override;
 
   void MapSharedMemory() override;
@@ -49,6 +70,14 @@ class AudioInputDevice::AudioThreadCallback
   std::vector<std::unique_ptr<media::AudioBus>> audio_buses_;
   CaptureCallback* capture_callback_;
 
+  // Used for informing AudioInputDevice that we have gotten data, i.e. the
+  // stream is alive. |got_data_callback_| is run every
+  // |got_data_callback_interval_in_frames_| frames, calculated from
+  // kGotDataCallbackIntervalSeconds.
+  const int got_data_callback_interval_in_frames_;
+  int frames_since_last_got_data_callback_;
+  base::RepeatingClosure got_data_callback_;
+
   DISALLOW_COPY_AND_ASSIGN(AudioThreadCallback);
 };
 
@@ -61,7 +90,8 @@ AudioInputDevice::AudioInputDevice(
       state_(IDLE),
       session_id_(0),
       agc_is_enabled_(false),
-      stopping_hack_(false) {
+      stopping_hack_(false),
+      missing_callbacks_detected_(false) {
   CHECK(ipc_);
 
   // The correctness of the code depends on the relative values assigned in the
@@ -146,12 +176,21 @@ void AudioInputDevice::OnStreamCreated(
   DCHECK(!audio_callback_);
   DCHECK(!audio_thread_);
   audio_callback_.reset(new AudioInputDevice::AudioThreadCallback(
-      audio_parameters_, handle, length, total_segments, callback_));
+      audio_parameters_, handle, length, total_segments, callback_,
+      base::BindRepeating(&AudioInputDevice::SetLastCallbackTimeToNow, this)));
   audio_thread_.reset(new AudioDeviceThread(audio_callback_.get(),
                                             socket_handle, "AudioInputDevice"));
 
   state_ = RECORDING;
   ipc_->RecordStream();
+
+  // Start detecting missing callbacks.
+  SetLastCallbackTimeToNowOnIOThread();
+  check_alive_timer_.Start(
+      FROM_HERE,
+      base::TimeDelta::FromSeconds(kCheckMissingCallbacksIntervalSeconds), this,
+      &AudioInputDevice::CheckIfInputStreamIsAlive);
+  DCHECK(check_alive_timer_.IsRunning());
 }
 
 void AudioInputDevice::OnError() {
@@ -222,6 +261,12 @@ void AudioInputDevice::StartUpOnIOThread() {
 void AudioInputDevice::ShutDownOnIOThread() {
   DCHECK(task_runner()->BelongsToCurrentThread());
 
+  check_alive_timer_.Stop();
+
+  UMA_HISTOGRAM_BOOLEAN("Media.Audio.Capture.DetectedMissingCallbacks",
+                        missing_callbacks_detected_);
+  missing_callbacks_detected_ = false;
+
   // Close the stream, if we haven't already.
   if (state_ >= CREATING_STREAM) {
     ipc_->CloseStream();
@@ -268,13 +313,33 @@ void AudioInputDevice::WillDestroyCurrentMessageLoop() {
   ShutDownOnIOThread();
 }
 
+void AudioInputDevice::CheckIfInputStreamIsAlive() {
+  DCHECK(task_runner()->BelongsToCurrentThread());
+  if (base::TimeTicks::Now() - last_callback_time_ >

[ossu-chromium, 2017/05/24 15:52:00]

nit: Should probably be >=, but I'm not going to enforce it . :)

[Henrik Grunell, 2017/05/24 17:18:10]

Maybe so, maybe so. Everything in this mechanism is low precision anyway, and
the likelihood of hitting equals here...

+      base::TimeDelta::FromSeconds(kMissingCallbacksTimeBeforeErrorSeconds)) {
+    callback_->OnCaptureError("No audio received from audio capture device.");
+    missing_callbacks_detected_ = true;
+  }
+}
+
+void AudioInputDevice::SetLastCallbackTimeToNow() {
+  task_runner()->PostTask(
+      FROM_HERE,
+      base::Bind(&AudioInputDevice::SetLastCallbackTimeToNowOnIOThread, this));
+}
+
+void AudioInputDevice::SetLastCallbackTimeToNowOnIOThread() {
+  last_callback_time_ = base::TimeTicks::Now();
+}
+
 // AudioInputDevice::AudioThreadCallback
 AudioInputDevice::AudioThreadCallback::AudioThreadCallback(
     const AudioParameters& audio_parameters,
     base::SharedMemoryHandle memory,
     int memory_length,
     int total_segments,
-    CaptureCallback* capture_callback)
+    CaptureCallback* capture_callback,
+    base::RepeatingClosure got_data_callback_)
     : AudioDeviceThread::Callback(audio_parameters,
                                   memory,
                                   memory_length,
@@ -283,7 +348,11 @@ AudioInputDevice::AudioThreadCallback::AudioThreadCallback(
                     base::Time::kMillisecondsPerSecond),
       current_segment_id_(0),
       last_buffer_id_(UINT32_MAX),
-      capture_callback_(capture_callback) {}
+      capture_callback_(capture_callback),
+      got_data_callback_interval_in_frames_(kGotDataCallbackIntervalSeconds *
+                                            audio_parameters.sample_rate()),
+      frames_since_last_got_data_callback_(0),
+      got_data_callback_(std::move(got_data_callback_)) {}
 
 AudioInputDevice::AudioThreadCallback::~AudioThreadCallback() {
 }
@@ -341,6 +410,14 @@ void AudioInputDevice::AudioThreadCallback::Process(uint32_t pending_data) {
   // Use pre-allocated audio bus wrapping existing block of shared memory.
   media::AudioBus* audio_bus = audio_buses_[current_segment_id_].get();
 
+  // Regularly inform that we have gotten data.
+  frames_since_last_got_data_callback_ += audio_bus->frames();
+  if (frames_since_last_got_data_callback_ >=
+      got_data_callback_interval_in_frames_) {
+    got_data_callback_.Run();
+    frames_since_last_got_data_callback_ = 0;
+  }
+
   // Deliver captured data to the client in floating point format and update
   // the audio delay measurement.
   capture_callback_->Capture(