diff -r 000000000000 -r 6474c204b198 js/src/ds/IdValuePair.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/ds/IdValuePair.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,29 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99:
+ * 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 ds_IdValuePair_h
+#define ds_IdValuePair_h
+
+#include "NamespaceImports.h"
+
+#include "js/Id.h"
+
+namespace js {
+
+struct IdValuePair
+{
+    jsid id;
+    Value value;
+
+    IdValuePair() {}
+    IdValuePair(jsid idArg)
+      : id(idArg), value(UndefinedValue())
+    {}
+};
+
+} /* namespace js */
+
+#endif /* ds_IdValuePair_h */