Round corners and add a transparent gap

Round all the corners of both the foreground and background components. Add a small transparent gap to separate the two.

Screen Recording: http://screencast/cast/NTM2MzUzNDc2NTQ5MDE3Nnw4ZDM5NWY3Ni0xNA

Bug: 409407482, 421985364
Change-Id: Icdd03e2231dc2416d492632348799748cdad13c1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6618124
Commit-Queue: Gazal Agarwal <agazal@google.com>
Reviewed-by: Wenyu Fu <wenyufu@chromium.org>
Reviewed-by: Peilin Wang <peilinwang@google.com>
Cr-Commit-Position: refs/heads/main@{#1471303}