New day, new tweak in Cydia. Developed by Ryan Petrich, BrowserChooser allows you to switch default browsers between Google Chrome, Opera Mini, iCab Mobile, Dolphing Browser, Atomic Browser, Diigo, iLunascape, MammothIV, Puffin, Mercury and Safari.
To install this tweak, add the following repo in Cydia: http://rpetri.ch/repo/