Ensures that audio tasks cannot run after AudioManager is deleted.

media/audio/alsa/audio_manager_alsa.h

 // Copyright 2013 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_ALSA_AUDIO_MANAGER_ALSA_H_
 #define MEDIA_AUDIO_ALSA_AUDIO_MANAGER_ALSA_H_
 
 #include <memory>
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/threading/thread.h"
 #include "media/audio/audio_manager_base.h"
 
 namespace media {
 
 class AlsaWrapper;
 
 class MEDIA_EXPORT AudioManagerAlsa : public AudioManagerBase {
  public:
   AudioManagerAlsa(
       scoped_refptr<base::SingleThreadTaskRunner> task_runner,
       scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner,
       AudioLogFactory* audio_log_factory);
+  ~AudioManagerAlsa() override;
 
   static void ShowLinuxAudioInputSettings();
 
   // Implementation of AudioManager.
+  void Shutdown() override;
   bool HasAudioOutputDevices() override;
   bool HasAudioInputDevices() override;
   void ShowAudioInputSettings() override;
   void GetAudioInputDeviceNames(AudioDeviceNames* device_names) override;
   void GetAudioOutputDeviceNames(AudioDeviceNames* device_names) override;
   AudioParameters GetInputStreamParameters(
       const std::string& device_id) override;
   const char* GetName() override;
 
   // Implementation of AudioManagerBase.
   AudioOutputStream* MakeLinearOutputStream(
       const AudioParameters& params,
       const LogCallback& log_callback) override;
   AudioOutputStream* MakeLowLatencyOutputStream(
       const AudioParameters& params,
       const std::string& device_id,
       const LogCallback& log_callback) override;
   AudioInputStream* MakeLinearInputStream(
       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;
 
  protected:
-  ~AudioManagerAlsa() override;
-
   AudioParameters GetPreferredOutputStreamParameters(
       const std::string& output_device_id,
       const AudioParameters& input_params) override;
 
  private:
   enum StreamType {
     kStreamPlayback = 0,
     kStreamCapture,
   };
 
@@ skipping 24 matching lines @@
                                     const std::string& device_id);
 
   std::unique_ptr<AlsaWrapper> wrapper_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioManagerAlsa);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_ALSA_AUDIO_MANAGER_ALSA_H_