Refactor Future constructors.

utils/pub/command_uploader.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.
 
 library command_uploader;
 
 import 'dart:async';
 import 'dart:io';
 import 'dart:uri';
 
@@ skipping 41 matching lines @@
     if (!['add', 'remove'].contains(command)) {
       log.error('Unknown uploader command "$command".');
       this.printUsage();
       exit(exit_codes.USAGE);
     } else if (commandOptions.rest.isEmpty) {
       log.error('No uploader given for "pub uploader $command".');
       this.printUsage();
       exit(exit_codes.USAGE);
     }
 
-    return new Future.of(() {
+    return new Future.sync(() {
       var package = commandOptions['package'];
       if (package != null) return package;
       return new Entrypoint(path.current, cache).root.name;
     }).then((package) {
       var uploader = commandOptions.rest[0];
       return oauth2.withClient(cache, (client) {
         if (command == 'add') {
           var url = server.resolve("/packages/${encodeUriComponent(package)}"
               "/uploaders.json");
           return client.post(url, fields: {"email": uploader});
         } else { // command == 'remove'
           var url = server.resolve("/packages/${encodeUriComponent(package)}"
               "/uploaders/${encodeUriComponent(uploader)}.json");
           return client.delete(url);
         }
       });
     }).then(handleJsonSuccess)
       .catchError((error) => handleJsonError(error.response),
                   test: (e) => e is PubHttpException);
   }
 }