Ensures that audio tasks cannot run after AudioManager is deleted.

media/audio/win/audio_manager_win.h

 // Copyright (c) 2012 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_WIN_AUDIO_MANAGER_WIN_H_
 #define MEDIA_AUDIO_WIN_AUDIO_MANAGER_WIN_H_
 
 #include <memory>
 #include <string>
 
 #include "base/macros.h"
 #include "media/audio/audio_manager_base.h"
 
 namespace media {
 
 class AudioDeviceListenerWin;
 
 // Windows implementation of the AudioManager singleton. This class is internal
 // to the audio output and only internal users can call methods not exposed by
 // the AudioManager class.
 class MEDIA_EXPORT AudioManagerWin : public AudioManagerBase {
  public:
   AudioManagerWin(
       scoped_refptr<base::SingleThreadTaskRunner> task_runner,
       scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner,
       AudioLogFactory* audio_log_factory);
+  ~AudioManagerWin() override;
 
   // Implementation of AudioManager.
+  void Shutdown() override;
   bool HasAudioOutputDevices() override;
   bool HasAudioInputDevices() override;
   base::string16 GetAudioInputDeviceModel() override;
   void ShowAudioInputSettings() override;
   void GetAudioInputDeviceNames(AudioDeviceNames* device_names) override;
   void GetAudioOutputDeviceNames(AudioDeviceNames* device_names) override;
   AudioParameters GetInputStreamParameters(
       const std::string& device_id) override;
   std::string GetAssociatedOutputDeviceID(
       const std::string& input_device_id) override;
@@ skipping 11 matching lines @@
       const AudioParameters& params,
       const std::string& device_id,
       const LogCallback& log_callback) override;
   AudioInputStream* MakeLowLatencyInputStream(
       const AudioParameters& params,
       const std::string& device_id,
       const LogCallback& log_callback) override;
   std::string GetDefaultOutputDeviceID() override;
 
  protected:
-  ~AudioManagerWin() override;
-
   AudioParameters GetPreferredOutputStreamParameters(
       const std::string& output_device_id,
       const AudioParameters& input_params) override;
 
  private:
   // Allow unit test to modify the utilized enumeration API.
   friend class AudioManagerTest;
 
   // Helper methods for performing expensive initialization tasks on the audio
   // thread instead of on the UI thread which AudioManager is constructed on.
   void InitializeOnAudioThread();
 
   void GetAudioDeviceNamesImpl(bool input, AudioDeviceNames* device_names);
 
   // Listen for output device changes.
   std::unique_ptr<AudioDeviceListenerWin> output_device_listener_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioManagerWin);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_WIN_AUDIO_MANAGER_WIN_H_