Provide enterprise policy option to set the minimum SSL version.

In order to address the POODLE attack, some large deployments of Chrome may
wish to disable SSLv3 before we make it a default. Equally, they may need to
preserve SSLv3 when we disable it by default.

BUG=419870

Review URL: https://codereview.chromium.org/649373002

Cr-Commit-Position: refs/heads/master@{#299755}
5 files changed