I voted Canelo would stop him within 8 rounds. Chavez has a very good chin and he will probably outweigh Canelo by about 15 pounds in the ring so maybe Canelo will need a round or two more to stop him.
Canelo will spend the first 3 cautiously, because he known Chavez can bang. Will spend the next 3 picking him apart. 6-9 will be a series of "OMG, Chavez has a chin!" with the ref finally saving Chavez in the 9th.