var file;

Cu.importGlobalProperties(["File"]);

addMessageListener("file.create", function (message) {

  file = Cc["@mozilla.org/file/directory_service;1"]

             .getService(Ci.nsIProperties)

             .get("TmpD", Ci.nsIFile);

  file.append("foo.txt");

  file.createUnique(Ci.nsIFile.NORMAL_FILE_TYPE, 0o600);

  File.createFromNsIFile(file).then(function(domFile) {

    sendAsyncMessage("file.created", domFile);

  });

});

addMessageListener("file.remove", function (message) {

  file.remove(false);

  sendAsyncMessage("file.removed", {});

});