Ensures that audio tasks cannot run after AudioManager is deleted.

media/audio/audio_manager_base.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_AUDIO_MANAGER_BASE_H_
 #define MEDIA_AUDIO_AUDIO_MANAGER_BASE_H_
 
 #include <memory>
 #include <string>
 #include <unordered_set>
@@ skipping 17 matching lines @@
 namespace media {
 
 class AudioOutputDispatcher;
 
 // AudioManagerBase provides AudioManager functions common for all platforms.
 class MEDIA_EXPORT AudioManagerBase : public AudioManager {
  public:
   ~AudioManagerBase() override;
 
   // AudioManager:
+  void Shutdown() override;
   base::string16 GetAudioInputDeviceModel() override;
   void ShowAudioInputSettings() override;
 
   void GetAudioInputDeviceDescriptions(
       AudioDeviceDescriptions* device_descriptions) final;
   void GetAudioOutputDeviceDescriptions(
       AudioDeviceDescriptions* device_descriptions) final;
 
   AudioOutputStream* MakeAudioOutputStream(
       const AudioParameters& params,
@@ skipping 61 matching lines @@
     return static_cast<int>(input_streams_.size());
   }
   int output_stream_count() const { return num_output_streams_; }
 
  protected:
   AudioManagerBase(
       scoped_refptr<base::SingleThreadTaskRunner> task_runner,
       scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner,
       AudioLogFactory* audio_log_factory);
 
-  // Releases all the audio output dispatchers.
-  // All audio streams should be closed before Shutdown() is called.
-  // This must be called in the destructor of every AudioManagerBase
-  // implementation.
-  void Shutdown();
-
   void SetMaxOutputStreamsAllowed(int max) { max_num_output_streams_ = max; }
 
   // Called by each platform specific AudioManager to notify output state change
   // listeners that a state change has occurred.  Must be called from the audio
   // thread.
   void NotifyAllOutputDeviceChangeListeners();
 
   // Returns user buffer size as specified on the command line or 0 if no buffer
   // size has been specified.
   static int GetUserBufferSize();
@@ skipping 70 matching lines @@
 
   // Debug recording manager.
   std::unique_ptr<AudioDebugRecordingManager> debug_recording_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioManagerBase);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_MANAGER_BASE_H_