> This is because the Mozilla Foundation refused to accept the Tor Project's commits to enhance privacy in the browser.
Actually, I'm pretty sure this is untrue. I'm reasonably certain we're actively working with the Tor Browser developers to get their patches merged into core (but preffed off) so that they don't have to maintain a stack of patches on top of Firefox.
(Disclaimer: Mozilla employee)
There are also tickets in Tor's TRAC issue tracker for Chrome. Once again, using Chrome securely would require several patches to source.