Ensures that audio tasks cannot run after AudioManager is deleted.

media/audio/android/audio_manager_android.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_ANDROID_AUDIO_MANAGER_ANDROID_H_
 #define MEDIA_AUDIO_ANDROID_AUDIO_MANAGER_ANDROID_H_
 
 #include <set>
 
 #include "base/android/jni_android.h"
 #include "base/macros.h"
 #include "base/synchronization/lock.h"
 #include "base/synchronization/waitable_event.h"
 #include "media/audio/audio_manager_base.h"
 
 namespace media {
 
 class OpenSLESOutputStream;
 
 // Android implemention of AudioManager.
 class MEDIA_EXPORT AudioManagerAndroid : public AudioManagerBase {
  public:
   AudioManagerAndroid(
       scoped_refptr<base::SingleThreadTaskRunner> task_runner,
       scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner,
       AudioLogFactory* audio_log_factory);
+  ~AudioManagerAndroid() override;
 
   void InitializeIfNeeded();
 
   // Implementation of AudioManager.
+  void Shutdown() override;
   bool HasAudioOutputDevices() override;
   bool HasAudioInputDevices() override;
   void GetAudioInputDeviceNames(AudioDeviceNames* device_names) override;
   void GetAudioOutputDeviceNames(AudioDeviceNames* device_names) override;
   AudioParameters GetInputStreamParameters(
       const std::string& device_id) override;
 
   AudioOutputStream* MakeAudioOutputStream(
       const AudioParameters& params,
       const std::string& device_id,
@@ skipping 28 matching lines @@
   void SetMute(JNIEnv* env,
                const base::android::JavaParamRef<jobject>& obj,
                jboolean muted);
 
   // Sets a volume that applies to all this manager's output audio streams.
   // This overrides other SetVolume calls (e.g. through AudioHostMsg_SetVolume).
   void SetOutputVolumeOverride(double volume);
   bool HasOutputVolumeOverride(double* out_volume) const;
 
  protected:
-  ~AudioManagerAndroid() override;
-
   AudioParameters GetPreferredOutputStreamParameters(
       const std::string& output_device_id,
       const AudioParameters& input_params) override;
 
  private:
   jobject GetJavaAudioManager();
   bool HasNoAudioInputStreams();
   void SetCommunicationAudioModeOn(bool on);
   bool SetAudioDevice(const std::string& device_id);
   int GetNativeOutputSampleRate();
@@ skipping 17 matching lines @@
   // If set, overrides volume level on output streams
   bool output_volume_override_set_;
   double output_volume_override_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioManagerAndroid);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_ANDROID_AUDIO_MANAGER_ANDROID_H_