Files related to the Lookalike URL and Safety Tip warnings.

The lookalike interstitial is triggered when a user visits a domain that is
similar to that of a domain of a popular site. See //docs/idn.md for details.

Safety Tip warnings are an experiment to warn users when Chrome believes a site
is low reputation, due either to client- or server-side checks. This warning may
either be a full-page interstitial warning or a pop-up while visiting the page.

Both warnings avoid triggering on sites that are likely to be benign, such as
popular sites, sites with a high site engagement.

