Make dartj2s do type conversions on constructor arguments

tests/html/fontface_test.dart

Index: tests/html/fontface_test.dart
diff --git a/tests/html/fontface_test.dart b/tests/html/fontface_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..8247a8a268e7e5c28401c3aed9a42b625ae7c77a
--- /dev/null
+++ b/tests/html/fontface_test.dart
@@ -0,0 +1,22 @@
+// 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.
+
+library fontface_test;
+
+import 'package:unittest/unittest.dart';
+import 'package:unittest/html_config.dart';
+
+import 'dart:html';
+
+main() {
+  useHtmlConfiguration();
+
+  test("Creation with parameters", () {
+    var font =
+        new FontFace('Ahem', 'url(Ahem.ttf)', {'variant': 'small-caps'});
+    expect(font is FontFace, isTrue);
+    expect(font.family, 'Ahem');
+    expect(font.variant, 'small-caps');
+  });
+}