diff -r 000000000000 -r 6474c204b198 content/base/src/nsDOMSettableTokenList.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/content/base/src/nsDOMSettableTokenList.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,33 @@
+/* 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/. */
+
+/*
+ * Implementation of DOMSettableTokenList specified by HTML5.
+ */
+
+#ifndef nsDOMSettableTokenList_h___
+#define nsDOMSettableTokenList_h___
+
+#include "nsDOMTokenList.h"
+
+class nsIAtom;
+
+// nsISupports must be on the primary inheritance chain
+// because nsDOMSettableTokenList is traversed by Element.
+class nsDOMSettableTokenList MOZ_FINAL : public nsDOMTokenList
+{
+public:
+
+  nsDOMSettableTokenList(mozilla::dom::Element* aElement, nsIAtom* aAttrAtom)
+    : nsDOMTokenList(aElement, aAttrAtom) {}
+
+  virtual JSObject* WrapObject(JSContext *cx) MOZ_OVERRIDE;
+
+  // WebIDL
+  void GetValue(nsAString& aResult) { Stringify(aResult); }
+  void SetValue(const nsAString& aValue, mozilla::ErrorResult& rv);
+};
+
+#endif // nsDOMSettableTokenList_h___
+