Introduce the TYPEDEF element, and use it in order to catch passing closures to the DOM. I make the…

frog/tests/native/src/NativeWrappingFunctionFrogTest.dart

+// Copyright (c) 2012, 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.
+
+typedef void Callback0();
+typedef void Callback1(arg1);
+typedef void Callback2(arg1, arg2);
+
+class A native "*A" {
+  foo0(Callback0 closure) native;
+  foo1(Callback1 closure, arg1) native;
+  foo2(Callback2 closure, arg1, arg2) native;
+}
+
+makeA() native;
+
+void setup() native """
+function A() {}
+A.prototype.foo0 = function(closure) { return closure(); };
+A.prototype.foo1 = function(closure, arg1) { return closure(arg1); };
+A.prototype.foo2 = function(closure, arg1, arg2) {
+  return closure(arg1, arg2);
+};
+makeA = function(){return new A;};
+""";
+
+
+main() {
+  setup();
+  var a = makeA();
+  Expect.equals(42, a.foo0(() => 42));
+  Expect.equals(43, a.foo1((arg1) => arg1, 43));
+  Expect.equals(44, a.foo2((arg1, arg2) => arg1 + arg2, 21, 23));
+
+  A aa = a;
+  Expect.equals(42, aa.foo0(() => 42));
+  Expect.equals(43, aa.foo1((arg1) => arg1, 43));
+  Expect.equals(44, aa.foo2((arg1, arg2) => arg1 + arg2, 21, 23));
+}