diff -r 000000000000 -r 6474c204b198 dom/base/nsDOMString.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/base/nsDOMString.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,21 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsDOMString_h___
+#define nsDOMString_h___
+
+#include "nsStringGlue.h"
+
+inline bool DOMStringIsNull(const nsAString& aString)
+{
+  return aString.IsVoid();
+}
+
+inline void SetDOMStringToNull(nsAString& aString)
+{
+  aString.SetIsVoid(true);
+}
+
+#endif /* nsDOMString_h___ */