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

tests/compiler/dart2js_native/subclassing_1_test.dart

Index: tests/compiler/dart2js_native/subclassing_1_test.dart
diff --git a/tests/compiler/dart2js_native/subclassing_1_test.dart b/tests/compiler/dart2js_native/subclassing_1_test.dart
index b90366a49ccd864fc00f2910973260655e8c508c..b86130f5fe3ba3ad064d7eadcc34fdb5ead28e6e 100644
--- a/tests/compiler/dart2js_native/subclassing_1_test.dart
+++ b/tests/compiler/dart2js_native/subclassing_1_test.dart
@@ -3,13 +3,14 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import "package:expect/expect.dart";
-import 'dart:_js_helper' show Creates, setNativeSubclassDispatchRecord;
+import 'dart:_js_helper' show Native, Creates, setNativeSubclassDispatchRecord;
 import 'dart:_interceptors' show findInterceptorForType;
 
 // Test that subclasses of native classes can be defined by setting the dispatch
 // record.
 
-class A native "A" {
+@Native("A")
+class A {
   foo(x) =>  '$x,${this.oof()}';
   oof() => 'A';
 }