Add generic interfaces for the sinks of the media stream audio track

content/renderer/media/peer_connection_audio_sink_owner.cc

+// Copyright 2013 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/peer_connection_audio_sink_owner.h"
+
+#include "content/renderer/media/webrtc_audio_device_impl.h"
+
+namespace content {
+
+PeerConnectionAudioSinkOwner::PeerConnectionAudioSinkOwner(
+    PeerConnectionAudioSink* sink)
+    : delegate_(sink) {
+}
+
+int PeerConnectionAudioSinkOwner::OnData(const int16* audio_data,
+                                         int sample_rate,
+                                         int number_of_channels,
+                                         int number_of_frames,
+                                         const std::vector<int>& channels,
+                                         int audio_delay_milliseconds,
+                                         int current_volume,
+                                         bool need_audio_processing,
+                                         bool key_pressed) {
+  base::AutoLock lock(lock_);
+  if (delegate_) {
+    return delegate_->OnData(audio_data,
+                             sample_rate,
+                             number_of_channels,
+                             number_of_frames,
+                             channels,
+                             audio_delay_milliseconds,
+                             current_volume,
+                             need_audio_processing,
+                             key_pressed);
+  }
+
+  return 0;
+}
+
+void PeerConnectionAudioSinkOwner::OnSetFormat(

[tommi (sloooow) - chröme, 2013/11/29 13:00:20]

can we add thread checks for functions that are expected to be called on the
main thread and document when we're on any other thread?

[no longer working on chromium, 2013/11/29 15:02:04]

as discussed offline, we can skip this for now since it will touch quite some
existing unittests

+    const media::AudioParameters& params) {
+  base::AutoLock lock(lock_);
+  if (delegate_)
+    delegate_->OnSetFormat(params);
+}
+
+void PeerConnectionAudioSinkOwner::Reset() {
+  base::AutoLock lock(lock_);
+  delegate_ = NULL;
+}
+
+bool PeerConnectionAudioSinkOwner::IsEqual(
+    const PeerConnectionAudioSink* other) const {
+  DCHECK(other);

[tommi (sloooow) - chröme, 2013/11/29 13:00:20]

nit: No need for this dcheck now.

[no longer working on chromium, 2013/11/29 15:02:04]

It is unclear to me, shouldn't the client take care that other won't be NULL ?

+  base::AutoLock lock(lock_);
+  return (other == delegate_);
+}
+
+}  // namespace content