Fix dartium bug handling object literal constructors with zero arguments.

tests/html/js_typed_interop_test.dart

Index: tests/html/js_typed_interop_test.dart
diff --git a/tests/html/js_typed_interop_test.dart b/tests/html/js_typed_interop_test.dart
index baf4d49c58d866af295c587035b6ac891382f838..2907142b0fe3c6a042ed98c8b292b0e0d29fc2f2 100644
--- a/tests/html/js_typed_interop_test.dart
+++ b/tests/html/js_typed_interop_test.dart
@@ -124,6 +124,12 @@ class ExampleLiteral {
   external num get z;
 }
 
+@anonymous
+@JS()
+class EmptyLiteral {
+  external factory EmptyLiteral();
+}
+
 @JS('Foob')
 class Foob extends Foo {
   external String get y;
@@ -180,6 +186,11 @@ main() {
       expect(l.z, equals(100));
       expect(stringify(l), equals('{"z":100}'));
     });
+
+    test('empty', () {
+      var l = new EmptyLiteral();
+      expect(stringify(l), equals('{}'));
+    });
   });
 
   group('constructor', () {