Introduce AudioHardwareConfig for renderer side audio device info.

content/renderer/media/audio_message_filter.cc

Index: content/renderer/media/audio_message_filter.cc
diff --git a/content/renderer/media/audio_message_filter.cc b/content/renderer/media/audio_message_filter.cc
index 22915c521c53264ededd36610bf119e14089c95c..4397720c4e89268b4c747fa14044788145d94a7b 100644
--- a/content/renderer/media/audio_message_filter.cc
+++ b/content/renderer/media/audio_message_filter.cc
@@ -23,21 +23,22 @@ AudioMessageFilter* AudioMessageFilter::Get() {
 
 AudioMessageFilter::AudioMessageFilter()
     : next_stream_id_(1),
-      channel_(NULL) {
+      channel_(NULL),
+      audio_hardware_config_(NULL) {
   DVLOG(1) << "AudioMessageFilter::AudioMessageFilter()";
   DCHECK(!filter_);
   filter_ = this;
 }
 
 int AudioMessageFilter::AddDelegate(media::AudioOutputIPCDelegate* delegate) {
-  base::AutoLock guard(delegates_lock_);
+  base::AutoLock auto_lock(lock_);
   const int id = next_stream_id_++;
   delegates_.insert(std::make_pair(id, delegate));
   return id;
 }
 
 void AudioMessageFilter::RemoveDelegate(int id) {
-  base::AutoLock guard(delegates_lock_);
+  base::AutoLock auto_lock(lock_);
   delegates_.erase(id);
 }
 
@@ -96,6 +97,7 @@ bool AudioMessageFilter::OnMessageReceived(const IPC::Message& message) {
   IPC_BEGIN_MESSAGE_MAP(AudioMessageFilter, message)
     IPC_MESSAGE_HANDLER(AudioMsg_NotifyStreamCreated, OnStreamCreated)
     IPC_MESSAGE_HANDLER(AudioMsg_NotifyStreamStateChanged, OnStreamStateChanged)
+    IPC_MESSAGE_HANDLER(AudioMsg_NotifyDeviceChanged, OnOutputDeviceChanged)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
@@ -115,7 +117,7 @@ void AudioMessageFilter::OnChannelClosing() {
 
   DelegateMap zombies;
   {
-    base::AutoLock guard(delegates_lock_);
+    base::AutoLock auto_lock(lock_);
     delegates_.swap(zombies);
   }
 
@@ -153,7 +155,7 @@ void AudioMessageFilter::OnStreamCreated(
 #endif
 
   {
-    base::AutoLock guard(delegates_lock_);
+    base::AutoLock auto_lock(lock_);
     DelegateMap::const_iterator it = delegates_.find(stream_id);
     if (it != delegates_.end()) {
       it->second->OnStreamCreated(handle, socket_handle, length);
@@ -169,7 +171,7 @@ void AudioMessageFilter::OnStreamCreated(
 
 void AudioMessageFilter::OnStreamStateChanged(
     int stream_id, media::AudioOutputIPCDelegate::State state) {
-  base::AutoLock guard(delegates_lock_);
+  base::AutoLock auto_lock(lock_);
   DelegateMap::const_iterator it = delegates_.find(stream_id);
   DLOG_IF(WARNING, it == delegates_.end())
       << "No delegate found for state change. " << state;
@@ -177,4 +179,22 @@ void AudioMessageFilter::OnStreamStateChanged(
     it->second->OnStateChanged(state);
 }
 
+void AudioMessageFilter::OnOutputDeviceChanged(int stream_id,
+                                               int new_buffer_size,
+                                               int new_sample_rate) {
+  base::AutoLock auto_lock(lock_);
+
+  // If an audio hardware config hasn't been created, ignore the message.

[scherkus (not reviewing), 2013/01/31 02:33:33]

nit: a more informative comment would suggest when this is possible (if it's
even possible!)

For example ... it looks like renderer processes only get sent this message if
there's an AudioEntry in AudioRendererHost that has this stream. In order for
that to be true, then someone must have created a stream first. Can we guarantee
that if a renderer has requested to create a stream that a_h_c_ has been
created?

[DaleCurtis, 2013/01/31 19:50:00]

Not until we remove the high latency audio path and flags like
--disable-renderer-side-mixing -- which I'd like to do the milestone after Linux
renderer side mixing lands and looks good.  I've updated the comment to include
this information for now.

+  if (!audio_hardware_config_)
+    return;
+
+  audio_hardware_config_->UpdateOutputConfig(new_buffer_size, new_sample_rate);
+}
+
+void AudioMessageFilter::SetAudioHardwareConfig(
+    media::AudioHardwareConfig* config) {
+  base::AutoLock auto_lock(lock_);
+  audio_hardware_config_ = config;
+}
+
 }  // namespace content