Remove redundancy in security interstitial UMA logic
Currently, very similar events are being recorded in different ways between the
Safe Browsing and SSL interstitials. This unifies the event types and shares a
common helper method between the two. It should be extensible to future
interstitials. It also has the pleasant side effect of reducing the overwhelming
complexity of the previous interstitial.ssl histogram.
BUG=
448487
Committed:
https://crrev.com/4cd6e60d57c83b5f7b3a6de4497329de7822e316
Cr-Commit-Position: refs/heads/master@{#312042}