I have the same problem, every time Avast actualizes it's Antivirus engine, it Installs Safe Zone, without my consent, and even they decide where to install it. And it is huge, 5.5 Gb, compared to Firefox 325 Mb, Chrome 481 Mb. And if you just use the Uninstall that comes with the program, it leaves several thousand files in my disk, that took to Revo Uninstaller to eliminate them more than 5 hours.
This is innaceptable. I have been using Avast Antivirus for more than 12 years, in my computers and my phone, and have been very satisfied with it's performance. But if this continues I will think to replace it with another Antivirus.
Is there a form to notify Avast that I do not want its Browser?