migration: Create a themed background for the folder icon ImageView

In order to update the background color dynamically for the folder icon
ImageView, create a themed background for it.

Fixed: 1361993
Change-Id: If8f24b46fa78750e5e652d5ce98a6cfb7667f09c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3888038


Reviewed-by: Toni Barzic <tbarzic@chromium.org>
Commit-Queue: Connie Xu <conniekxu@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1045349}