Forward the number of skipped frames by the OS in audio playout.

media/audio/audio_output_controller.cc

Index: media/audio/audio_output_controller.cc
diff --git a/media/audio/audio_output_controller.cc b/media/audio/audio_output_controller.cc
index 8aa2b4f38acfdfa989986ab5f4b035c3f1627bc9..9ddafe4a78d46bb66156240ceb74599f0dbaedcb 100644
--- a/media/audio/audio_output_controller.cc
+++ b/media/audio/audio_output_controller.cc
@@ -36,7 +36,8 @@ AudioOutputController::AudioOutputController(
           params.sample_rate(),
           TimeDelta::FromMilliseconds(kPowerMeasurementTimeConstantMillis)),
       on_more_io_data_called_(0),
-      ignore_errors_during_stop_close_(false) {
+      ignore_errors_during_stop_close_(false),
+      frames_skipped_(0) {
   DCHECK(audio_manager);
   DCHECK(handler_);
   DCHECK(sync_reader_);
@@ -160,7 +161,7 @@ void AudioOutputController::DoPlay() {
     return;
 
   // Ask for first packet.
-  sync_reader_->UpdatePendingBytes(0);
+  sync_reader_->UpdatePendingBytes(0, 0);
 
   state_ = kPlaying;
 
@@ -213,7 +214,7 @@ void AudioOutputController::DoPause() {
   // Let the renderer know we've stopped.  Necessary to let PPAPI clients know
   // audio has been shutdown.  TODO(dalecurtis): This stinks.  PPAPI should have
   // a better way to know when it should exit PPB_Audio_Shared::Run().
-  sync_reader_->UpdatePendingBytes(kuint32max);
+  sync_reader_->UpdatePendingBytes(kuint32max, 0);
 
   handler_->OnPaused();
 }
@@ -293,8 +294,11 @@ int AudioOutputController::OnMoreData(AudioBus* dest,
   sync_reader_->Read(dest);
 
   const int frames = dest->frames();
-  sync_reader_->UpdatePendingBytes(base::saturated_cast<uint32>(
-      total_bytes_delay + frames * params_.GetBytesPerFrame()));
+  sync_reader_->UpdatePendingBytes(
+      base::saturated_cast<uint32>(total_bytes_delay +

[tommi (sloooow) - chröme, 2015/12/01 13:34:25]

this saturated cast looks like a hack. :-/

Can we at least pull it out of this expression since total_bytes_delay is
already the right type, and do:

uint32_t frame_bytes = base::saturated_cast<uint32>(frames *
params_.GetBytesPerFrame());
sync_reader_->UpdatePendingBytes(total_bytes_delay + frame_bytes);

Even so, frame_bytes should never overflow, so maybe we could do something more
drastic if it ever does (if we need to).

[Henrik Grunell, 2015/12/03 17:01:07]

Agree, I don't know why we would fear it overflowing.

+                                   frames * params_.GetBytesPerFrame()),
+      frames_skipped_);
+  frames_skipped_ = 0;
 
   if (will_monitor_audio_levels())
     power_monitor_.Scan(*dest, frames);
@@ -302,6 +306,12 @@ int AudioOutputController::OnMoreData(AudioBus* dest,
   return frames;
 }
 
+void AudioOutputController::OnSkippedData(uint32 frames_skipped) {

[tommi (sloooow) - chröme, 2015/12/01 13:34:25]

thread check

[Henrik Grunell, 2015/12/03 17:01:06]

Done.

+  // Store the number of skipped frames, will be passed to the provider in
+  // OnMoreData().
+  frames_skipped_ += frames_skipped;
+}
+
 void AudioOutputController::OnError(AudioOutputStream* stream) {
   {
     base::AutoLock auto_lock(error_lock_);