Add @anonymous annotation and restrict object literal constructors to only anonymous classes. This …

tests/html/js_typed_interop_test.dart

 // Copyright (c) 2015, 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.
 
 @JS()
 library js_typed_interop_test;
 
 import 'dart:html';
 
 import 'package:js/js.dart';
@@ skipping 96 matching lines @@
   external set x(int v);
   external num multiplyByX(num y);
   external num multiplyBy2(num y);
   external callClosureWithArgAndThis(Function closure, arg);
   external callClosureWithArg1(Function closure, arg1);
   external callClosureWithArg2(Function closure, arg1, arg2);
   external Bar getBar();
   external static int multiplyDefault2(int a, [int b]);
 }
 
+@anonymous
 @JS()
 class ExampleLiteral {
   external factory ExampleLiteral({int x, String y, num z});
 
   external int get x;
   external String get y;
   external num get z;
 }
 
 @JS('Foob')
@@ skipping 205 matching lines @@
       // We do know at runtime whether something is a JsArray or not.
       expect(foo is List, isFalse);
     });
 
     test('dart interfaces', () {
       expect(foo is Function, isFalse);
       expect(selection is List, isTrue);
     });
   });
 }