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

dart/lib/compiler/implementation/native_emitter.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.
 
 class NativeEmitter {
 
   CodeEmitterTask emitter;
   StringBuffer nativeBuffer;
 
   // Classes that participate in dynamic dispatch. These are the
@@ skipping 159 matching lines @@
   void potentiallyConvertDartClosuresToJs(StringBuffer code,
                                           FunctionElement member) {
     FunctionSignature parameters = member.computeSignature(compiler);
     Element converter =
         compiler.findHelper(const SourceString('convertDartClosureToJS'));
     String closureConverter = compiler.namer.isolateAccess(converter);
     parameters.forEachParameter((Element parameter) {
       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');
       }
     });
   }
 
   String generateParameterStub(Element member,
                                String invocationName,
                                String stubParameters,
                                List<String> argumentsBuffer,
                                int indexOfLastOptionalArgumentInParameters,
                                StringBuffer buffer) {
@@ skipping 202 matching lines @@
     String toStringName = compiler.namer.instanceMethodName(
         null, const SourceString('toString'), 0);
     objectProperties.add("$defPropName(Object.prototype, '$toStringName', ");
     objectProperties.add(
         'function() { return $toStringHelperName(this); });\n');
 
     targetBuffer.add('$defineNativeClassName = $defineNativeClassFunction;\n');
     targetBuffer.add('$objectProperties$nativeBuffer\n');
   }
 }