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

tests/compiler/dart2js_native/native_class_inheritance2_frog_test.dart

 // Copyright (c) 2011, 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 "dart:_js_helper";
 import "package:expect/expect.dart";
 
 // Test to see if resolving a hidden native class's method interferes with
 // subsequent resolving the subclass's method.  This might happen if the
 // superclass caches the method in the prototype, so shadowing the dispatcher
 // stored on Object.prototype.
 
-class A native "A" {
+@Native("A")
+class A {
   foo([a=100]) native;
 }
 
-class B extends A native "B" {
+@Native("B")
+class B extends A {
 }
 
-class C extends B native "C" {
+@Native("C")
+class C extends B {
   foo([z=300]) native;
 }
 
-class D extends C native "D" {
+@Native("D")
+class D extends C {
 }
 
 makeA() native;
 makeB() native;
 makeC() native;
 makeD() native;
 
 void setup() native """
 // This code is all inside 'setup' and so not accesible from the global scope.
 function inherits(child, parent) {
@@ skipping 37 matching lines @@
   Expect.equals('C.foo(300)', d.foo());
   // If the above line fails with C.foo(100) then the dispatch to fill in the
   // default got the wrong one, followed by a second dispatch that resolved to
   // the correct native method.
 
   Expect.equals('A.foo(1)', a.foo(1));
   Expect.equals('A.foo(2)', b.foo(2));
   Expect.equals('C.foo(3)', c.foo(3));
   Expect.equals('C.foo(4)', d.foo(4));
 }