Modernize the style.

test/utils.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 utils;
-
 import 'dart:async';
 import 'dart:collection' show Queue;
 
 import 'package:http/http.dart' as http;
 import 'package:http/testing.dart';
 import 'package:oauth2/oauth2.dart' as oauth2;
 import 'package:test/test.dart';
 
 class ExpectClient extends MockClient {
   final Queue<MockClientHandler> _handlers;
@@ skipping 46 matching lines @@
 
 /// A matcher for functions that throw ExpirationException.
 const Matcher throwsExpirationException =
     const Throws(isExpirationException);
 
 class _ExpirationException extends TypeMatcher {
   const _ExpirationException() : super("ExpirationException");
   bool matches(item, Map matchState) =>
     item is oauth2.ExpirationException;
 }