Refactor Future constructors.

pkg/intl/lib/intl_browser.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /**
  * This provides facilities for Internationalization that are only available
  * when running in the web browser. You should import only one of this or
  * intl_standalone.dart. Right now the only thing provided here is the
  * ability to find the default locale from the browser.
  */
 
 library intl_browser;
 
 import "dart:async";
 import "dart:html";
 import "intl.dart";
 
 // TODO(alanknight): The need to do this by forcing the user to specially
 // import a particular library is a horrible hack, only done because there
 // seems to be no graceful way to do this at all. Either mirror access on
 // dart2js or the ability to do spawnUri in the browser would be promising
 // as ways to get rid of this requirement.
 /**
  * Find the system locale, accessed as window.navigator.language, and
  * set it as the default for internationalization operations in the
  * [Intl.systemLocale] variable.
  */
 Future<String> findSystemLocale() {
   Intl.systemLocale = Intl.canonicalizedLocale(window.navigator.language);
-  return new Future.immediate(Intl.systemLocale);
+  return new Future.value(Intl.systemLocale);
 }