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

tests/compiler/dart2js_native/subclassing_4_test.dart

 // Copyright (c) 2013, 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.
 
 import "package:expect/expect.dart";
-import 'dart:_js_helper' show Creates, setNativeSubclassDispatchRecord;
+import 'dart:_js_helper' show Native, Creates, setNativeSubclassDispatchRecord;
 import 'dart:_interceptors' show Interceptor, findInterceptorForType;
 
 // Test calling convention on subclasses of native classes.
 
 class M {
   miz() => 'M';
 }
 
-class N native "N" {}
+@Native("N")
+class N {}
 
 class A extends N {}
 
 class B extends A with M {
   // The call to [miz] has a know type [B].  The call is in an intercepted
   // method and to an intercepted method, so the ambient interceptor can be
   // used.  For correct optimization of the interceptor, the compiler needs to
   // (1) correctly determine that B is an intercepted type (because it extends a
   // native class) and (2) realize that the intersection of [B] and subclasses
   // of mixin applications of [M] is non-empty.
@@ skipping 12 matching lines @@
 """;
 
 main() {
   setup();
 
   setNativeSubclassDispatchRecord(getBPrototype(), findInterceptorForType(B));
 
   B b = makeB();
   Expect.equals('M', b.callMiz());
 }