Provide a constructor for (DOM)FormData, and rename to the more standard name,

lib/dom/dom.dart

 #library('dart:dom_deprecated');
 
 // 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.
 
 // DO NOT EDIT
 // Auto-generated Dart DOM library with no implementation.
 
 
@@ skipping 51 matching lines @@
 // 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 _FileReaderSyncFactoryProvider {
   factory FileReaderSync() => _dummy();
 }
 // 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 _FormDataFactoryProvider {
+  factory FormData([FormElement form]) => _dummy();
+}
+// 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 _HTMLAudioElementFactoryProvider {
   factory HTMLAudioElement([String src]) => _dummy();
 }
 // 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 _HTMLOptionElementFactoryProvider {
   factory HTMLOptionElement([String data, String value, bool defaultSelected, bool selected]) => _dummy();
 }
@@ skipping 1443 matching lines @@
   final String name;
 
   final DirectoryEntrySync root;
 }
 // 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.
 
 // WARNING: Do not edit - generated code.
 
-interface FormData {
-
-  void append(String name, String value, String filename);
-}
-
-interface DOMFormData extends FormData {
-}
-// 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.
-
-// WARNING: Do not edit - generated code.
-
 interface DOMImplementation {
 
   CSSStyleSheet createCSSStyleSheet(String title, String media);
 
   Document createDocument(String namespaceURI, String qualifiedName, DocumentType doctype);
 
   DocumentType createDocumentType(String qualifiedName, String publicId, String systemId);
 
   HTMLDocument createHTMLDocument(String title);
 
@@ skipping 1598 matching lines @@
   void setElements(Object array, [int offset]);
 
   Float64Array subarray(int start, [int end]);
 }
 // 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.
 
 // WARNING: Do not edit - generated code.
 
+interface FormData default _FormDataFactoryProvider {
+
+  FormData([FormElement form]);
+
+  void append(String name, String value, String filename);
+}
+// 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.
+
+// WARNING: Do not edit - generated code.
+
 interface Gamepad {
 
   final List<num> axes;
 
   final List<num> buttons;
 
   final String id;
 
   final int index;
 
@@ skipping 9934 matching lines @@
 // 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.
 
 Window get window() => _dummy();
 
 // TODO(vsm): Remove when prefixes are supported.
 Window get dom_window() => _dummy();
 
 Document get document() => _dummy();