[kirkmc adds: Interesting. On my Mac, in the bundle, in Contents > Versions, there are, indeed, two versions of Chrome. This presumably has something to do with Chrome's silent updating. (Queries on Twitter suggest that this is the norm; a number of people replied that theirs was around 220 MB, as was mine.) Make sure you keep the one with the highest version number. You could also, of course, just download a new copy.
If you want to turn off this automatic updating, see this hint from 2010.]

