promisify functions with `successCallback`/`errorCallback` arguments using https://github.com/slightlyoff/Promises

example.js

var service = ...; // webinos file api service

promisify(service.requestFileSystem, service)(null, null)
.then(function (filesystem) {
  return filesystem.root;
})
.then(function (root) {
  return promisify(root.getFile, root)("test", { create : true });
})
.then(function (file) {
  console.log(file.name);
});

promisify.js

function promisify(fun, thisArg) {
  return function () {
    var argsArray = Array.prototype.slice.call(arguments);
    return new Promise(function (resolver) {
      argsArray.push(resolver.fulfill.bind(resolver));
      argsArray.push(resolver.reject.bind(resolver));
      fun.apply(thisArg, argsArray);
    });
  };
};