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

lib/dom/dart2js/dom_dart2js.dart

 #library('dart:dom_deprecated');
 
 // 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.
 
 // DO NOT EDIT
 // Auto-generated Dart DOM library.
 
 
@@ skipping 993 matching lines @@
   final _DirectoryEntryJs root;
 }
 
 class _DOMFileSystemSyncJs extends _DOMTypeJs implements DOMFileSystemSync native "*DOMFileSystemSync" {
 
   final String name;
 
   final _DirectoryEntrySyncJs root;
 }
 
-class _DOMFormDataJs extends _DOMTypeJs implements DOMFormData native "*DOMFormData" {
-
-  void append(String name, String value, String filename) native;
-}
-
 class _DOMImplementationJs extends _DOMTypeJs implements DOMImplementation native "*DOMImplementation" {
 
   _CSSStyleSheetJs createCSSStyleSheet(String title, String media) native;
 
   _DocumentJs createDocument(String namespaceURI, String qualifiedName, _DocumentTypeJs doctype) native;
 
   _DocumentTypeJs createDocumentType(String qualifiedName, String publicId, String systemId) native;
 
   _HTMLDocumentJs createHTMLDocument(String title) native;
 
@@ skipping 1551 matching lines @@
   List<num> getRange(int start, int rangeLength) =>
       _Lists.getRange(this, start, rangeLength, <num>[]);
 
   // -- end List<num> mixins.
 
   void setElements(Object array, [int offset]) native 'set';
 
   _Float64ArrayJs subarray(int start, [int end]) native;
 }
 
+class _FormDataJs extends _DOMTypeJs implements FormData native "*FormData" {
+
+  void append(String name, String value, String filename) native;
+}
+
 class _GamepadJs extends _DOMTypeJs implements Gamepad native "*Gamepad" {
 
   final List<num> axes;
 
   final List<num> buttons;
 
   final String id;
 
   final int index;
 
@@ skipping 9505 matching lines @@
 // BSD-style license that can be found in the LICENSE file.
 
 class _FileReaderSyncFactoryProvider {
   factory FileReaderSync() native
       '''return new FileReaderSync();''';
 }
 // 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]) native
+      '''return new FormData(form);''';
+}
+// 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 = null]) native
 '''
 if (src == null) return new Audio();
 return new Audio(src);
 ''';
 }
 // 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.
@@ skipping 1491 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 10259 matching lines @@
     if (length < 0) throw new IllegalArgumentException('length');
     if (start < 0) throw new IndexOutOfRangeException(start);
     int end = start + length;
     if (end > a.length) throw new IndexOutOfRangeException(end);
     for (int i = start; i < end; i++) {
       accumulator.add(a[i]);
     }
     return accumulator;
   }
 }