Support DOMString[] and regenerate from IDL

client/dom/generated/src/wrapping/_DOMFormDataWrappingImplementation.dart

 // Copyright (c) 2011, 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.
 
 // WARNING: Do not edit - generated code.
 
 class _DOMFormDataWrappingImplementation extends DOMWrapperBase implements DOMFormData {
   _DOMFormDataWrappingImplementation() : super() {}
 
   static create__DOMFormDataWrappingImplementation() native {
     return new _DOMFormDataWrappingImplementation();
   }
 
-  void append(String name, String value) {
-    _append(this, name, value);
+  void append(String name, String value, String filename) {
+    _append(this, name, value, filename);
     return;
   }
-  static void _append(receiver, name, value) native;
+  static void _append(receiver, name, value, filename) native;
 
   String get typeName() { return "DOMFormData"; }
 }