Add a policy control feature to restrict the font-display

* The feature is currently behind the "ExperimentalProductivityFeatures" runtime flag


Change-Id: I059a8d1becd98609ac1ac972e5623af266605586
Reviewed-on: https://chromium-review.googlesource.com/c/1412795
Reviewed-by: Ken Buchanan <kenrb@chromium.org>
Reviewed-by: Ian Clelland <iclelland@chromium.org>
Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Commit-Queue: Yashar Dabiran <yashard@google.com>
Cr-Commit-Position: refs/heads/master@{#624640}
10 files changed