The Canonical developers did not give up on the ideea of replacing Mozilla Firefox with Google’s Chromium, as the default internet browser on Ubuntu 13.10 Saucy Salamander.
Chromium became at least as fast as Firefox, at web surfing and has competitive features too, so the Ubuntu team finds this a good move.
The Firefox fans should not be sad, however, Firefox will still be available in the default repositories so an installation is a peace of cake.
There is still no official announcement of this replacement, but I think it will took place, because there are too many rumours.