Cleanup: Introduce AsyncFileTestHelper for testing with async file/quota operations

content/content_tests.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': 'test_support_content',
       'type': 'static_library',
       'defines!': ['CONTENT_IMPLEMENTATION'],
@@ skipping 403 matching lines @@
         '../webkit/database/database_quota_client_unittest.cc',
         '../webkit/database/databases_table_unittest.cc',
         '../webkit/database/database_tracker_unittest.cc',
         '../webkit/database/database_util_unittest.cc',
         '../webkit/dom_storage/dom_storage_area_unittest.cc',
         '../webkit/dom_storage/dom_storage_cached_area_unittest.cc',
         '../webkit/dom_storage/dom_storage_context_unittest.cc',
         '../webkit/dom_storage/dom_storage_database_unittest.cc',
         '../webkit/dom_storage/dom_storage_map_unittest.cc',
         '../webkit/dom_storage/session_storage_database_unittest.cc',
+        '../webkit/fileapi/async_file_test_helper.cc',
+        '../webkit/fileapi/async_file_test_helper.h',
         '../webkit/fileapi/external_mount_points_unittest.cc',
         '../webkit/fileapi/file_system_context_unittest.cc',
         '../webkit/fileapi/file_system_database_test_helper.cc',
         '../webkit/fileapi/file_system_database_test_helper.h',
         '../webkit/fileapi/file_system_directory_database_unittest.cc',
         '../webkit/fileapi/file_system_dir_url_request_job_unittest.cc',
         '../webkit/fileapi/file_system_file_stream_reader_unittest.cc',
         '../webkit/fileapi/file_system_file_util_unittest.cc',
         '../webkit/fileapi/file_system_mount_point_provider_unittest.cc',
         '../webkit/fileapi/file_system_origin_database_unittest.cc',
@@ skipping 609 matching lines @@
             'additional_src_dirs': ['../content/public/android/javatests/',],
             'resource_dir': '../shell_apk/res',
             'is_test_apk': 1,
           },
           'includes': [ '../build/java_apk.gypi' ],
         },
       ],
     }],
   ],
 }