function showOpenDialog(allowMultipleSelection, chooseDirectories, title, initialPath, fileTypes, callback) {
        appshell.fs.showOpenDialog(allowMultipleSelection, chooseDirectories, title, initialPath, fileTypes, _wrap(callback));
    }
Display an open-files dialog to the user and call back asynchronously with
either a FileSystmError string or an array of path strings, which indicate
the entry or entries selected.

@param {boolean} allowMultipleSelection
@param {boolean} chooseDirectories
@param {string} title
@param {string} initialPath
@param {Array.<string>=} fileTypes
@param {function(?string, Array.<string>=)} callback