Share one thread between all AudioOutputControllers instead of creating one per stream.

media/audio/linux/audio_manager_linux.h

 // Copyright (c) 2010 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.
 
 #ifndef MEDIA_AUDIO_LINUX_AUDIO_MANAGER_LINUX_H_
 #define MEDIA_AUDIO_LINUX_AUDIO_MANAGER_LINUX_H_
 
 #include <map>
 
 #include "base/lock.h"
 #include "base/ref_counted.h"
 #include "base/scoped_ptr.h"
 #include "base/thread.h"
-#include "media/audio/audio_io.h"
+#include "media/audio/audio_manager_base.h"
 
 class AlsaPcmOutputStream;
 class AlsaWrapper;
 
-class AudioManagerLinux : public AudioManager {
+class AudioManagerLinux : public AudioManagerBase {
  public:
   AudioManagerLinux();
 
   // Call before using a newly created AudioManagerLinux instance.
   virtual void Init();
 
   // Implementation of AudioManager.
   virtual bool HasAudioOutputDevices();
   virtual bool HasAudioInputDevices();
   virtual AudioOutputStream* MakeAudioOutputStream(Format format, int channels,
                                                    int sample_rate,
                                                    char bits_per_sample);
   virtual AudioInputStream* MakeAudioInputStream(Format format, int channels,
                                                  int sample_rate,
                                                  char bits_per_sample,
                                                  uint32 samples_per_packet);
   virtual void MuteAll();
   virtual void UnMuteAll();
 
   virtual void ReleaseOutputStream(AlsaPcmOutputStream* stream);
 
  protected:
   // Friend function for invoking the destructor at exit.
   friend void DestroyAudioManagerLinux(void*);
   virtual ~AudioManagerLinux();
 
  private:
-  // Thread used to interact with AudioOutputStreams created by this
-  // audio manger.
-  base::Thread audio_thread_;
   scoped_ptr<AlsaWrapper> wrapper_;
 
   Lock lock_;
   std::map<AlsaPcmOutputStream*, scoped_refptr<AlsaPcmOutputStream> >
       active_streams_;
 
-  bool initialized_;
-
   DISALLOW_COPY_AND_ASSIGN(AudioManagerLinux);
 };
 
 #endif  // MEDIA_AUDIO_LINUX_AUDIO_MANAGER_LINUX_H_