Refactor Future constructors.

utils/tests/pub/validator/size_test.dart

 // Copyright (c) 2013, 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.
 
 import 'dart:async';
 import 'dart:math' as math;
 
 import 'package:scheduled_test/scheduled_test.dart';
 
 import '../../../pub/entrypoint.dart';
 import '../../../pub/validator.dart';
 import '../../../pub/validator/size.dart';
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 import 'utils.dart';
 
 Function size(int size) {
   return (entrypoint) =>
-      new SizeValidator(entrypoint, new Future.immediate(size));
+      new SizeValidator(entrypoint, new Future.value(size));
 }
 
 main() {
   initConfig();
 
   setUp(d.validPackage.create);
 
   integration('should consider a package valid if it is <= 10 MB', () {
     expectNoValidationError(size(100));
     expectNoValidationError(size(10 * math.pow(2, 20)));
   });
 
   integration('should consider a package invalid if it is more than 10 MB', () {
     expectValidationError(size(10 * math.pow(2, 20) + 1));
   });
 }