Make MediaFileUtil run on thread pool.

webkit/fileapi/webkit_fileapi.gypi

 # 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.
 
 {
   'targets': [
     {
       'target_name': 'fileapi',
       'type': '<(component)',
       'variables': { 'enable_wexit_time_destructors': 1, },
@@ skipping 28 matching lines @@
         'file_system_operation_interface.h',
         'file_system_options.cc',
         'file_system_options.h',
         'file_system_origin_database.cc',
         'file_system_origin_database.h',
         'file_system_quota_client.cc',
         'file_system_quota_client.h',
         'file_system_quota_util.cc',
         'file_system_quota_util.h',
         'file_system_types.h',
+        'file_system_task_runners.cc',
+        'file_system_task_runners.h',
         'file_system_url.cc',
         'file_system_url.h',
         'file_system_url_request_job.cc',
         'file_system_url_request_job.h',
         'file_system_url_request_job_factory.cc',
         'file_system_url_request_job_factory.h',
         'file_system_usage_cache.cc',
         'file_system_usage_cache.h',
         'file_system_util.cc',
         'file_system_util.h',
@@ skipping 63 matching lines @@
             '../chromeos/fileapi/remote_file_system_operation.h',
             '../chromeos/fileapi/remote_file_system_proxy.h',
             '../chromeos/fileapi/remote_file_stream_writer.cc',
             '../chromeos/fileapi/remote_file_stream_writer.h',
           ],
         }],
       ],
     },
   ],
 }