Ensures that audio tasks cannot run after AudioManager is deleted.

chromecast/media/audio/cast_audio_manager.h

 // Copyright 2015 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 CHROMECAST_MEDIA_AUDIO_CAST_AUDIO_MANAGER_H_
 #define CHROMECAST_MEDIA_AUDIO_CAST_AUDIO_MANAGER_H_
 
 #include "base/macros.h"
 #include "media/audio/audio_manager_base.h"
 
@@ skipping 12 matching lines @@
       scoped_refptr<base::SingleThreadTaskRunner> task_runner,
       scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner,
       ::media::AudioLogFactory* audio_log_factory,
       MediaPipelineBackendManager* backend_manager);
   CastAudioManager(
       scoped_refptr<base::SingleThreadTaskRunner> task_runner,
       scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner,
       ::media::AudioLogFactory* audio_log_factory,
       MediaPipelineBackendManager* backend_manager,
       CastAudioMixer* audio_mixer);
+  ~CastAudioManager() override;
 
   // AudioManager implementation.
   bool HasAudioOutputDevices() override;
   bool HasAudioInputDevices() override;
   void ShowAudioInputSettings() override;
   void GetAudioInputDeviceNames(
       ::media::AudioDeviceNames* device_names) override;
   ::media::AudioParameters GetInputStreamParameters(
       const std::string& device_id) override;
   const char* GetName() override;
 
   // AudioManagerBase implementation
   void ReleaseOutputStream(::media::AudioOutputStream* stream) override;
 
   // This must be called on audio thread.
   virtual std::unique_ptr<MediaPipelineBackend> CreateMediaPipelineBackend(
       const MediaPipelineDeviceParams& params);
 
- protected:
-  ~CastAudioManager() override;
-
  private:
   // AudioManagerBase implementation.
   ::media::AudioOutputStream* MakeLinearOutputStream(
       const ::media::AudioParameters& params,
       const ::media::AudioManager::LogCallback& log_callback) override;
   ::media::AudioOutputStream* MakeLowLatencyOutputStream(
       const ::media::AudioParameters& params,
       const std::string& device_id,
       const ::media::AudioManager::LogCallback& log_callback) override;
   ::media::AudioInputStream* MakeLinearInputStream(
@@ skipping 16 matching lines @@
   std::unique_ptr<::media::AudioOutputStream> mixer_output_stream_;
   std::unique_ptr<CastAudioMixer> mixer_;
 
   DISALLOW_COPY_AND_ASSIGN(CastAudioManager);
 };
 
 }  // namespace media
 }  // namespace chromecast
 
 #endif  // CHROMECAST_MEDIA_AUDIO_CAST_AUDIO_MANAGER_H_