This change makes the "policy" field required for all preloaded entries
and validates its content.
The actual value isn't used by the generator and does not become part
of the binary output. The policy field will be used for list
maintenance (an auto-roller and automated pruning).
Bug: 778047
Change-Id: I485a55e17e0d3aa4f97f8605cceeeef9ba355ed4
Reviewed-on: https://chromium-review.googlesource.com/782724
Reviewed-by: Ryan Sleevi <rsleevi@chromium.org>
Commit-Queue: Martijn Croonen <martijnc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#519135}