Consider randomizing the resolution passed to xvfb

[pyoor]

It might be worth considering setting a random resolution to xvfb as this might affect layout. Similar concept to the TTF Fuzzer outlined here:

https://media.blackhat.com/bh-eu-12/Lee/bh-eu-12-Lee-GDI_Font_Fuzzing-WP.pdf

Agree, eg: https://www.mozilla.org/en-US/security/advisories/mfsa2015-107/