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

media/audio/audio_manager_base.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_AUDIO_MANAGER_BASE_H_
+#define MEDIA_AUDIO_AUDIO_MANAGER_BASE_H_
+
+#include "base/thread.h"
+#include "media/audio/audio_manager.h"
+
+// AudioManagerBase provides AudioManager functions common for all platforms.
+class AudioManagerBase : public AudioManager {
+ public:
+  AudioManagerBase();
+
+  virtual void Init();
+
+  virtual MessageLoop* GetMessageLoop();
+
+ protected:
+  virtual ~AudioManagerBase() {}
+
+  bool initialized() { return initialized_; }
+
+ protected:
+  // Thread used to interact with AudioOutputStreams created by this
+  // audio manger.
+  base::Thread audio_thread_;
+
+  bool initialized_;
+
+  DISALLOW_COPY_AND_ASSIGN(AudioManagerBase);
+};
+
+#endif  // MEDIA_AUDIO_AUDIO_MANAGER_BASE_H_