Part 3.4: Is policy list subsumed under subsuming policy?

In this patch we consider special keywords such as `unsafe-eval`,
`unsafe-hashed-attributes`, `strict-dynamic`.

BUG=647588

Review-Url: https://codereview.chromium.org/2538623003
Cr-Commit-Position: refs/heads/master@{#435957}
2 files changed