Certificate path builder for new certificate verification library

Builds paths from a target certificate to a trust anchor and attempts to verify them according to RFC 5280. Supports asynchronous intermediate lookups (eg, AIA fetching) and backtracking.

This implementation uses a depth-first strategy which is simple and uses minimal resources, but may not be optimal.


Review-Url: https://codereview.chromium.org/1923433002
Cr-Commit-Position: refs/heads/master@{#404239}
29 files changed