Bug 1037461. mfbt: Add a MakeUnique variant that takes 5 arguments.

mfbt/UniquePtr.h

@@ -634,6 +634,13 @@ MakeUnique(A1&& a1, A2&& a2, A3&& a3, A4&& a4)
   return UniquePtr<T>(new T(Forward<A1>(a1), Forward<A2>(a2), Forward<A3>(a3), Forward<A4>(a4)));
 }
 
+template<typename T, typename A1, typename A2, typename A3, typename A4, typename A5>
+typename detail::UniqueSelector<T>::SingleObject
+MakeUnique(A1&& a1, A2&& a2, A3&& a3, A4&& a4, A5&& a5)
+{
+  return UniquePtr<T>(new T(Forward<A1>(a1), Forward<A2>(a2), Forward<A3>(a3), Forward<A4>(a4), Forward<A5>(a5)));
+}
+
 template<typename T>
 typename detail::UniqueSelector<T>::UnknownBound
 MakeUnique(decltype(sizeof(int)) n)