Here is a short tip to avoid having the red warning page in google chrome for https (SSL) websites you trust (ie: https websites with self-signed certificates), we can usse certutil to add the certificate.
First, check you have libnss3-tools package installed or install it :
sudo apt-get install libnss3-tools
Then here is how you can add a self-signed certificate according to this chromium project wiki page.
certutil -d sql:$HOME/.pki/nssdb -A -t "P,," -n <certificate_name> -i </path/to/certificate_file>
<certificate_name> is the name of the certificate,
</path/to/certificate_file> is the path to the imported certificate file (absolute or relative path)
This command allow to list certificates :
certutil -d sql:$HOME/.pki/nssdb -L # list certificates, append -n <certificate nickname> for cert details