diff -r 000000000000 -r 6474c204b198 js/src/vm/NumberObject.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/vm/NumberObject.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,46 @@
+/* -*- 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 vm_NumberObject_h
+#define vm_NumberObject_h
+
+#include "jsnum.h"
+
+namespace js {
+
+class NumberObject : public JSObject
+{
+    /* Stores this Number object's [[PrimitiveValue]]. */
+    static const unsigned PRIMITIVE_VALUE_SLOT = 0;
+
+  public:
+    static const unsigned RESERVED_SLOTS = 1;
+
+    static const Class class_;
+
+    /*
+     * Creates a new Number object boxing the given number.  The object's
+     * [[Prototype]] is determined from context.
+     */
+    static inline NumberObject *create(JSContext *cx, double d);
+
+    double unbox() const {
+        return getFixedSlot(PRIMITIVE_VALUE_SLOT).toNumber();
+    }
+
+  private:
+    inline void setPrimitiveValue(double d) {
+        setFixedSlot(PRIMITIVE_VALUE_SLOT, NumberValue(d));
+    }
+
+    /* For access to init, as Number.prototype is special. */
+    friend JSObject *
+    ::js_InitNumberClass(JSContext *cx, js::HandleObject global);
+};
+
+} // namespace js
+
+#endif /* vm_NumberObject_h */