Revert 57254 - Share one thread between all AudioOutputControllers instead of...

media/audio/audio_manager.cc

-// 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.
-
-#include "media/audio/audio_manager.h"
-
-#include "base/at_exit.h"
-#include "base/logging.h"
-
-namespace {
-
-AudioManager* g_audio_manager = NULL;
-
-// NullAudioManager is the audio manager used on the systems that have no
-// audio support.
-class NullAudioManager : public AudioManager {
- public:
-  NullAudioManager() { }
-
-  // Implementation of AudioManager.
-  virtual bool HasAudioOutputDevices() { return false; }
-  virtual bool HasAudioInputDevices() { return false; }
-  virtual AudioOutputStream* MakeAudioOutputStream(Format format, int channels,
-                                                   int sample_rate,
-                                                   char bits_per_sample) {
-    NOTIMPLEMENTED();
-    return NULL;
-  }
-  virtual AudioInputStream* MakeAudioInputStream(Format format, int channels,
-                                                 int sample_rate,
-                                                 char bits_per_sample,
-                                                 uint32 samples_per_packet) {
-    NOTIMPLEMENTED();
-    return NULL;
-  }
-  virtual void MuteAll() { NOTIMPLEMENTED(); }
-  virtual void UnMuteAll() { NOTIMPLEMENTED(); }
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(NullAudioManager);
-};
-
-}  // namespace
-
-// static
-void AudioManager::Destroy(void* not_used) {
-  delete g_audio_manager;
-  g_audio_manager = NULL;
-}
-
-// static
-AudioManager* AudioManager::GetAudioManager() {
-  if (!g_audio_manager) {
-    g_audio_manager = CreateAudioManager();
-    g_audio_manager->Init();
-    base::AtExitManager::RegisterCallback(&AudioManager::Destroy, NULL);
-  }
-  return g_audio_manager;
-}