🚫Bind: components/flags_ui/

Migrates some directories off of deprecated base::Bind, base::Callback,
etc, and onto the newer APIs.

Specifically this covers components/flags_ui/

Fixed: 1007691
Change-Id: I467a2c4866c6bd8498b4e74bfe31a81417f8d69e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1978818
Commit-Queue: Ken Rockot <rockot@google.com>
Auto-Submit: Ken Rockot <rockot@google.com>
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#726928}