You seem to believe that Google cares about Chrome more than their Firefox contract. I don't see this being likely. Chrome makes Google no money besides having Google as the default search. Firefox makes Google money in exactly the same way. Firefox is just as important to Google's revenue as Chrome is.
All Google needs is search results to show advertisements on and a browser capable of running their applications. Both Firefox and Chrome meet this requirement.
> Chrome makes Google no money besides having Google as the default search. Firefox makes Google money in exactly the same way. Firefox is just as important to Google's revenue as Chrome is.
You forget that Google pays Mozilla a lot of money for something they can get for free every time a Chrome installation replaces a Firefox installation. So the potential savings for Google is (currently) $300M/year once they have killed off Firefox completely.
All Google needs is search results to show advertisements on and a browser capable of running their applications. Both Firefox and Chrome meet this requirement.