Fix userVisibility for files in ChromeOS filesystems.

Source/modules/modules.gypi

 {
   'includes': [
     '../core/core_generated.gypi',
     'modules_generated.gypi',
   ],
   'variables': {
     # Experimental hooks for embedder to provide extra IDL and source files.
     #
     # Note: this is not a supported API. If you rely on this, you will be broken
     # from time to time as the code generator changes in backward incompatible
@@ skipping 1003 matching lines @@
       'navigatorcontentutils/testing/NavigatorContentUtilsClientMock.cpp',
       'navigatorcontentutils/testing/NavigatorContentUtilsClientMock.h',
       'speech/testing/InternalsSpeechSynthesis.cpp',
       'speech/testing/InternalsSpeechSynthesis.h',
       'speech/testing/PlatformSpeechSynthesizerMock.cpp',
       'speech/testing/PlatformSpeechSynthesizerMock.h',
       'vibration/testing/InternalsVibration.cpp',
       'vibration/testing/InternalsVibration.h',
     ],
     'modules_unittest_files': [
+      'filesystem/DOMFileSystemBaseTest.cpp',
       'indexeddb/IDBKeyPathTest.cpp',
       'indexeddb/IDBRequestTest.cpp',
       'indexeddb/IDBTransactionTest.cpp',
       'serviceworkers/RequestTest.cpp',
       'serviceworkers/ResponseTest.cpp',
       'serviceworkers/ServiceWorkerContainerTest.cpp',
       'websockets/DOMWebSocketTest.cpp',
       'websockets/NewWebSocketChannelImplTest.cpp',
       'websockets/WebSocketDeflaterTest.cpp',
       'websockets/WebSocketExtensionDispatcherTest.cpp',
       'websockets/WebSocketExtensionParserTest.cpp',
       'websockets/WebSocketPerMessageDeflateTest.cpp',
     ],
   },
 }