Automated IWYU fix for TaskRunner includes.

media/audio/mock_audio_manager.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_MOCK_AUDIO_MANAGER_H_
 #define MEDIA_AUDIO_MOCK_AUDIO_MANAGER_H_
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/sequenced_task_runner_helpers.h"
+#include "base/single_thread_task_runner.h"
 #include "media/audio/audio_manager.h"
 
 namespace media {
 
 // This class is a simple mock around AudioManager, used exclusively for tests,
 // which avoids to use the actual (system and platform dependent) AudioManager.
 // Some bots does not have input devices, thus using the actual AudioManager
 // would causing failures on classes which expect that.
 class MockAudioManager : public AudioManager {
  public:
@@ skipping 80 matching lines @@
   GetDeviceDescriptionsCallback get_input_device_descriptions_cb_;
   GetDeviceDescriptionsCallback get_output_device_descriptions_cb_;
   GetAssociatedOutputDeviceIDCallback get_associated_output_device_id_cb_;
 
   DISALLOW_COPY_AND_ASSIGN(MockAudioManager);
 };
 
 }  // namespace media.
 
 #endif  // MEDIA_AUDIO_MOCK_AUDIO_MANAGER_H_