Add 'part of' in dart2js code.

lib/compiler/implementation/util/util_implementation.dart

Index: lib/compiler/implementation/util/util_implementation.dart
diff --git a/lib/compiler/implementation/util/util_implementation.dart b/lib/compiler/implementation/util/util_implementation.dart
index ed4228a41ee1f3720ba36623d2f16b541d442cbb..bbb852ab86377779568e2fce6cb8c00191096993 100644
--- a/lib/compiler/implementation/util/util_implementation.dart
+++ b/lib/compiler/implementation/util/util_implementation.dart
@@ -2,6 +2,8 @@
 // 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('util_implementation');
-#import('util.dart');
-#source('link_implementation.dart');
+library util_implementation;
+
+import 'util.dart';
+
+part 'link_implementation.dart';