[Background Fetch] Cleanup after large refactor.

Few more minor changes that didn't make it in cr/1297412.

Bug: 850512
Change-Id: I7a1070135aa4d10a238c8c12fd4a95ffeac34343
Reviewed-on: https://chromium-review.googlesource.com/c/1320130
Commit-Queue: Rayan Kanso <rayankans@chromium.org>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606026}
3 files changed