Revert 176228

> Improve thread safety for device changes on OSX.
> 
> Device changes are hard, lets go shopping!  Sadly OSX does not handle property
> listener callbacks in a thread safe manner.  On 10.6 we can set
> kAudioHardwarePropertyRunLoop to account for this.  On 10.7 this is broken
> and we need to create a dispatch queue to drive callbacks.  However code
> running on the dispatch queue must be mutually exclusive with code running
> on the audio thread.
> 
> ExclusiveDispatchQueueTaskObserver works around this by pausing and resuming
> the dispatch queue before and after each pumped task.  Benchmarks on my retina
> 10.8.2 macbook pro show on average this takes < 30us in total.  No performance
> issues were seen even using FakeAudioOutputStream which drives audio callbacks
> on the message loop.
> 
> Complicating matters it the fact that the AudioProperty(Add|Remove)ListenerBlock
> functions are not available on 10.6... so we need to dynamically load them :-/
> 
> This is not ideal and long term we should replace the audio thread on OSX with a
> dispatch queue to avoid having to suspend/resume the queue; this is non-trivial
> and requires a significant refactoring of the AudioManager to support.
> 
> BUG=158170
> TEST=media_unittests. manual device changes.
> 
> Review URL: https://codereview.chromium.org/11824018

Fails on 10.6 :(

TBR=dalecurtis@google.com
Review URL: https://codereview.chromium.org/11840005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@176230 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 6 insertions, 6 deletions

diff --git a/media/audio/mac/audio_manager_mac.h b/media/audio/mac/audio_manager_mac.h
index 40ed54e..d8b6b2d 100644
--- a/media/audio/mac/audio_manager_mac.h
+++ b/media/audio/mac/audio_manager_mac.h
@@ -9,7 +9,6 @@
 #include "base/compiler_specific.h"
 #include "base/message_loop_proxy.h"
 #include "media/audio/audio_manager_base.h"
-#include "media/audio/mac/audio_device_listener_mac.h"
 
 namespace media {
 
@@ -38,15 +37,16 @@ class MEDIA_EXPORT AudioManagerMac : public AudioManagerBase {
   virtual AudioParameters GetPreferredLowLatencyOutputStreamParameters(
       const AudioParameters& input_params) OVERRIDE;
 
+  // Called by an internal device change listener.  Must be called on
+  // |creating_message_loop_|.
+  void OnDeviceChange();
+
  protected:
   virtual ~AudioManagerMac();
 
  private:
-  // Helper methods for constructing AudioDeviceListenerMac on the audio thread.
-  void CreateDeviceListener();
-  void DestroyDeviceListener();
-
-  scoped_ptr<AudioDeviceListenerMac> output_device_listener_;
+  bool listener_registered_;
+  scoped_refptr<base::MessageLoopProxy> creating_message_loop_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioManagerMac);
 };