GitLab

Add cr-settings-a11y-page and cr-settings-downloads-page to
md-settings.

Follow-up to http://crrev.com/1007803003.

Screenshot: http://i.imgur.com/qT28Xqo.png (colors are a bit off due to chromoting, will upload another tomorrow)

BUG=464979
R=stevenjb@chromium.org,jhawkins@chromium.org

Review URL: https://codereview.chromium.org/1013833003

Cr-Commit-Position: refs/heads/master@{#321194}