Adding Keygen to Policy List

Adding the Keygen setting to the Policy Configuration list.

BUG=514767

Review URL: https://codereview.chromium.org/1587653002

Cr-Commit-Position: refs/heads/master@{#370343}
(cherry picked from commit b4ac7fc14dfc0e46607defb902cad59623cef55b)

Review URL: https://codereview.chromium.org/1638453003 .

Cr-Commit-Position: refs/branch-heads/2623@{#118}
Cr-Branched-From: 92d77538a86529ca35f9220bd3cd512cbea1f086-refs/heads/master@{#369907}
5 files changed