Fix a crash in MimeHandlerServiceImpl::AbortStream().

extensions/extensions_tests.gyp

 {
   'variables': {
     # Product name is used for Mac bundle.
     'app_shell_product_name': 'App Shell',
     # The version is high enough to be supported by Omaha (at least 31)
     # but fake enough to be obviously not a Chrome release.
     'app_shell_version': '38.1234.5678.9',
     'chromium_code': 1,
   },
   'targets': [
@@ skipping 41 matching lines @@
         'browser/api/cast_channel/keep_alive_delegate_unittest.cc',
         'browser/api/cast_channel/logger_unittest.cc',
         'browser/api/cast_channel/test_util.cc',
         'browser/api/cast_channel/test_util.h',
         'browser/api/declarative/declarative_rule_unittest.cc',
         'browser/api/declarative/deduping_factory_unittest.cc',
         'browser/api/declarative/rules_registry_unittest.cc',
         'browser/api/declarative_webrequest/webrequest_condition_unittest.cc',
         'browser/api/declarative_webrequest/webrequest_condition_attribute_unittest.cc',
         'browser/api/idle/idle_api_unittest.cc',
+        'browser/api/mime_handler_private/mime_handler_private_unittest.cc',
         'browser/api/power/power_api_unittest.cc',
         'browser/api/sockets_tcp/sockets_tcp_api_unittest.cc',
         'browser/api/sockets_udp/sockets_udp_api_unittest.cc',
         'browser/api/storage/settings_quota_unittest.cc',
         'browser/api/storage/storage_api_unittest.cc',
         'browser/api/storage/storage_frontend_unittest.cc',
         'browser/api/web_request/form_data_parser_unittest.cc',
         'browser/api/web_request/upload_data_presenter_unittest.cc',
         'browser/api/web_request/web_request_time_tracker_unittest.cc',
         'browser/app_window/app_window_geometry_cache_unittest.cc',
@@ skipping 171 matching lines @@
             '../build/isolate.gypi',
           ],
           'sources': [
             'extensions_browsertests.isolate',
           ],
         },
       ],
     }],
   ],
 }