Remove AudioBuffersState usage in Chromium

media/audio/audio_output_controller.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 "media/audio/audio_output_controller.h"
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
 #include "base/metrics/histogram.h"
 #include "base/task_runner_util.h"
@@ skipping 262 matching lines @@
     OnDeviceChange();
 }
 
 void AudioOutputController::DoReportError() {
   DCHECK(message_loop_->BelongsToCurrentThread());
   if (state_ != kClosed)
     handler_->OnError();
 }
 
 int AudioOutputController::OnMoreData(AudioBus* dest,
-                                      AudioBuffersState buffers_state) {
+                                      int total_bytes_delay) {

[palmer, 2014/09/18 18:39:40]

void AudioSyncReader::UpdatePendingBytes(uint32 bytes)

int != uint32 in signedness and possibly even in width (ILP64).

(UpdatePendingBytes is correct to be defined as taking uint32; thus, change
|total_bytes_delay| to be uint32.)

[acolwell GONE FROM CHROMIUM, 2014/09/19 17:16:46]

Done.

   TRACE_EVENT0("audio", "AudioOutputController::OnMoreData");
 
   // Indicate that we haven't wedged (at least not indefinitely, WedgeCheck()
   // may have already fired if OnMoreIOData() took an abnormal amount of time).
   // Since this thread is the only writer of |on_more_io_data_called_| once the
   // thread starts, its safe to compare and then increment.
   if (base::AtomicRefCountIsZero(&on_more_io_data_called_))
     base::AtomicRefCountInc(&on_more_io_data_called_);
 
   sync_reader_->Read(dest);
 
   const int frames = dest->frames();
   sync_reader_->UpdatePendingBytes(
-      buffers_state.total_bytes() + frames * params_.GetBytesPerFrame());
+      total_bytes_delay + frames * params_.GetBytesPerFrame());

[palmer, 2014/09/18 18:39:40]

I see this:

// media::AudioOutputController::SyncReader implementations.
void AudioSyncReader::UpdatePendingBytes(uint32 bytes) {
  // Zero out the entire output buffer to avoid stuttering/repeating-buffers
  // in the anomalous case if the renderer is unable to keep up with real-time.
  output_bus_->Zero();
  socket_->Send(&bytes, sizeof(bytes));
  ++buffer_index_;
}

But, after we send |bytes| on the socket, what does the receiver do with the
value? (I'm sorry, I am not familiar with the audio code, so I don't know
off-hand.) Can you show me how integer overflow doesn't matter for how the
receiver uses the value?

[acolwell GONE FROM CHROMIUM, 2014/09/19 17:16:46]

The receiver of this value is in AudioDeviceThread::Thread::Run(). The Receive()
call was actually using an int instead of a uint32, which I have fixed in the
latest patch. Thanks for being persistant on this point. :)

 
   if (will_monitor_audio_levels())
     power_monitor_.Scan(*dest, frames);
 
   return frames;
 }
 
 void AudioOutputController::OnError(AudioOutputStream* stream) {
   // Handle error on the audio controller thread.
   message_loop_->PostTask(FROM_HERE, base::Bind(
@@ skipping 101 matching lines @@
   DCHECK(message_loop_->BelongsToCurrentThread());
 
   // If we should be playing and we haven't, that's a wedge.
   if (state_ == kPlaying) {
     UMA_HISTOGRAM_BOOLEAN("Media.AudioOutputControllerPlaybackStartupSuccess",
                           base::AtomicRefCountIsOne(&on_more_io_data_called_));
   }
 }
 
 }  // namespace media