Convert various uses of "callback list" to base::CallbackList.

This ensures these places also use the most specific naming schemes
possible.

Bug: 1113007
Change-Id: I87800caf53c214410a0bd1d3a04064019ac09404
AX-Relnotes: n/a.
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2343777
Commit-Queue: Allen Bauer <kylixrd@chromium.org>
Reviewed-by: Allen Bauer <kylixrd@chromium.org>
Reviewed-by: Jamie Walch <jamiewalch@chromium.org>
Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
Reviewed-by: Orin Jaworski <orinj@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Varun Khaneja <vakh@chromium.org>
Reviewed-by: John Wu <jzw@chromium.org>
Reviewed-by: David Benjamin <davidben@chromium.org>
Auto-Submit: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#798759}