This works for self-signed certificates
The flag would need to be added in the autostart file in /home/pi/.config/lxsession/LXDE-pi/autostart
--ignore-certificate-errors --test-type
More information available here: https://superuser.com/questions/27268/how-do-i-disable-the-warning-chrome-gives-if-a-security-certificate-is-not-trust