Snap , just read somewhere the firefox browsers also got internal backing from Google :/
Mozilla Corporation is wholly owned by the Mozilla Foundation, which is driven by its mission and is not controlled by any other entity: https://www.mozilla.org/mission/
But because mozilla is so dependent of the Google money, they can use it to "blackmail", to push some decisions down the mozilla throat, or even worse, to cut the payment in a blink wherever they want and if fits their strategy.. so mozilla are in a pretty dangerous position, given that theres a conflict of interests, since Google have created Chrome..
i think maybe thats why they are trying to go with FirefoxOS? another source of revenue and financial independence?