According to http://dev.w3.org/2009/dap/file-system/pub/FileSystem/#the-fileentry-interface , the first parameter (successCallback) to the createWriter() and file() methods is required. This test calls these methods without the required argument and logs the result. WebKit passes this test.
Created attachment 110239 [details] Patch
Comment on attachment 110239 [details] Patch This is redundant with http://trac.webkit.org/browser/trunk/LayoutTests/fast/filesystem/not-enough-arguments.html