Add tests for policy AllowDeletingBrowserHistory

Change-Id: I8db4b6ac9afd6f54d0f9cb5defea72456f4f2b87
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1713708
Commit-Queue: Fei Ling <feiling@chromium.org>
Reviewed-by: Owen Min <zmin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#682935}
4 files changed