We know Floyd can take a shot the question is whether Canelo can take shots as he is going to be hit consistently on the button and get abused as he has never been before. Its amazing that people despite evidence to the contrary doubt Floyd'spunching power.
Mayweather has one of the better chins in or around his division. (That said a KO is always a possibility against a bigger puncher)
Floyd has proven to have a good chin. Even better than chin is how he recovers quickly. See the 2 fights he was hurt worst in, (Chop Chop and Shane). by the end of the round he was walking the opponent down in both cases.