diff -r 000000000000 -r 6474c204b198 dom/bindings/RootedDictionary.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/bindings/RootedDictionary.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,56 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
+/* vim: set ts=2 sw=2 et tw=79: */
+/* 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 mozilla_dom_RootedDictionary_h__
+#define mozilla_dom_RootedDictionary_h__
+
+#include "mozilla/GuardObjects.h"
+#include "mozilla/dom/Nullable.h"
+#include "jsapi.h"
+
+namespace mozilla {
+namespace dom {
+
+template<typename T>
+class MOZ_STACK_CLASS RootedDictionary : public T,
+                                         private JS::CustomAutoRooter
+{
+public:
+  RootedDictionary(JSContext* cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM) :
+    T(),
+    JS::CustomAutoRooter(cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT)
+  {
+  }
+
+  virtual void trace(JSTracer *trc) MOZ_OVERRIDE
+  {
+    this->TraceDictionary(trc);
+  }
+};
+
+template<typename T>
+class MOZ_STACK_CLASS NullableRootedDictionary : public Nullable<T>,
+                                                 private JS::CustomAutoRooter
+{
+public:
+  NullableRootedDictionary(JSContext* cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM) :
+    Nullable<T>(),
+    JS::CustomAutoRooter(cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT)
+  {
+  }
+
+  virtual void trace(JSTracer *trc) MOZ_OVERRIDE
+  {
+    if (!this->IsNull()) {
+      this->Value().TraceDictionary(trc);
+    }
+  }
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif /* mozilla_dom_RootedDictionary_h__ */