diff -r 000000000000 -r 6474c204b198 js/src/jsboolinlines.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jsboolinlines.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,38 @@
+/* -*- 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 jsboolinlines_h
+#define jsboolinlines_h
+
+#include "jsbool.h"
+
+#include "vm/BooleanObject.h"
+#include "vm/WrapperObject.h"
+
+namespace js {
+
+bool
+BooleanGetPrimitiveValueSlow(HandleObject);
+
+inline bool
+BooleanGetPrimitiveValue(HandleObject obj)
+{
+    if (obj->is<BooleanObject>())
+        return obj->as<BooleanObject>().unbox();
+
+    return BooleanGetPrimitiveValueSlow(obj);
+}
+
+inline bool
+EmulatesUndefined(JSObject *obj)
+{
+    JSObject *actual = MOZ_LIKELY(!obj->is<WrapperObject>()) ? obj : UncheckedUnwrap(obj);
+    return actual->getClass()->emulatesUndefined();
+}
+
+} /* namespace js */
+
+#endif /* jsboolinlines_h */