Commit Martin's patch for pub + lib_v2.

utils/pub/validator/pubspec_field.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 pubspec_field_validator;
 
+import 'dart:async';
+
 import '../entrypoint.dart';
 import '../system_cache.dart';
 import '../validator.dart';
 import '../version.dart';
 
 /// A validator that checks that the pubspec has valid "author" and "homepage"
 /// fields.
 class PubspecFieldValidator extends Validator {
   PubspecFieldValidator(Entrypoint entrypoint)
     : super(entrypoint);
@@ skipping 33 matching lines @@
     }
 
     var version = pubspec.fields['version'];
     if (version == null) {
       errors.add('Your pubspec.yaml is missing a "version" field.');
     }
 
     return new Future.immediate(null);
   }
 }