Make oauth2 warning-clean.

pkg/oauth2/lib/src/credentials.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 credentials;
 
 import 'dart:async';
 import 'dart:json' as JSON;
 import 'dart:uri';
 
@@ skipping 32 matching lines @@
   final List<String> scopes;
 
   /// The date at which these credentials will expire. This is likely to be a
   /// few seconds earlier than the server's idea of the expiration date.
   final DateTime expiration;
 
   /// Whether or not these credentials have expired. Note that it's possible the
   /// credentials will expire shortly after this is called. However, since the
   /// client's expiration date is kept a few seconds earlier than the server's,
   /// there should be enough leeway to rely on this.
-  bool get isExpired => expiration != null && new DateTime.now() > expiration;
+  bool get isExpired => expiration != null &&
+      new DateTime.now().isAfter(expiration);
 
   /// Whether it's possible to refresh these credentials.
   bool get canRefresh => refreshToken != null && tokenEndpoint != null;
 
   /// Creates a new set of credentials.
   ///
   /// This class is usually not constructed directly; rather, it's accessed via
   /// [Client.credentials] after a [Client] is created by
   /// [AuthorizationCodeGrant]. Alternately, it may be loaded from a serialized
   /// form via [Credentials.fromJson].
@@ skipping 119 matching lines @@
       if (credentials.refreshToken != null) return credentials;
       return new Credentials(
           credentials.accessToken,
           this.refreshToken,
           credentials.tokenEndpoint,
           credentials.scopes,
           credentials.expiration);
     });
   }
 }