The pre-loaded list of sites in chrome can be found here
The link at the bottom of that page takes you to the ongoing code review for additional sites.
To manage HSTS sites in Dragon, open:
about:net-internals then select HSTS
You can check if a site is pre-loaded by using the Query domain option and you can add sites by using the Add domain. Be careful selecting the 'include sub-domains' option. Also remember, for HSTS to work, the web site has to have a HSTS policy enabled.