Add @Native(...) annotation for native class names.

tests/compiler/dart2js_native/field_type2_test.dart

Index: tests/compiler/dart2js_native/field_type2_test.dart
diff --git a/tests/compiler/dart2js_native/field_type2_test.dart b/tests/compiler/dart2js_native/field_type2_test.dart
index 15dbf61117bc6bdfc33e0fdc6552d29733a72030..6f8c35bf301c57e1a69f290173897ca651d5c712 100644
--- a/tests/compiler/dart2js_native/field_type2_test.dart
+++ b/tests/compiler/dart2js_native/field_type2_test.dart
@@ -5,7 +5,10 @@
 // Test that a closure call on a native field is recognized by the
 // type inferrer.
 
-class Node native "Node" {
+import 'dart:_js_helper';
+
+@Native("Node")
+class Node {
   final parentNode;
 }