Instead of border, content, padding the values now specified in the draft are border-box, content-box and padding-box. We need to just support both types of values on our -webkit- version of the properties. If/when we drop the -webkit-, then we can drop the old values from the final version.
Created attachment 28938 [details] Patch
Comment on attachment 28938 [details] Patch r=me
Fixed in r41979.
Some layout tests fixed in r41993.