Use the typedef arity to know how to invoke a closure given by the dom.

dart/lib/compiler/implementation/native_emitter.dart

Index: dart/lib/compiler/implementation/native_emitter.dart
===================================================================
--- dart/lib/compiler/implementation/native_emitter.dart	(revision 8049)
+++ dart/lib/compiler/implementation/native_emitter.dart	(working copy)
@@ -177,7 +177,7 @@
       Type type = parameter.computeType(compiler);
       if (type is FunctionType) {
         String name = parameter.name.slowToString();
-        code.add('  $name = $closureConverter($name);\n');
+        code.add('  $name = $closureConverter($name, ${type.arity()});\n');
       }
     });
   }