I can tell you a way to do it to make it last. They do sell chrome in a rattle can, if you prep it really good, use a good primer, then chrome, then a clear overcoat, while letting each coat dry inbetween you can have a great looking bumper for a fraction of the cost of having it chromed.
I have done this and if you take your time and prep and prep, it will turn out good and last all with rattle cans.