GitLab

We do not need any bottom inset for the separate message center bubble.
Also, need to clip scroller height based on clear all button visibility.

Bug: 958020
Change-Id: Ie4f0966f2de97f841cf975fcc7810c82761b2de2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1730091
Commit-Queue: Ahmed Mehfooz <amehfooz@chromium.org>
Reviewed-by: Tim Song <tengs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#683669}