Ensures that audio tasks cannot run after AudioManager is deleted.

media/audio/test_audio_thread.h

+// Copyright 2017 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_TEST_AUDIO_THREAD_H_
+#define MEDIA_AUDIO_TEST_AUDIO_THREAD_H_
+
+#include "base/memory/ref_counted.h"
+#include "base/threading/thread_checker.h"
+#include "media/audio/audio_thread.h"
+
+namespace media {
+
+class TestAudioThread : public AudioThread {
+ public:
+  TestAudioThread();
+  ~TestAudioThread() override;
+
+  // AudioThread implementation.
+  void Stop() override;
+  base::SingleThreadTaskRunner* GetTaskRunner() override;
+  base::SingleThreadTaskRunner* GetWorkerTaskRunner() override;
+
+ private:
+  base::ThreadChecker thread_checker_;
+  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestAudioThread);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_AUDIO_TEST_AUDIO_THREAD_H_