GitLab

This CL is part of the Code Health Rotation
(https://sites.google.com/corp/google.com/chrome-code-health/) and
changes the two remaining occurrences in chrome/test/base of
base::Closure to base::OnceClosure, as they are used in a waiter method
that can only be invoked once.

Bug: 1007643
Change-Id: If7040fe9041e88cfa89314224d98423aa6696432
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2623193Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Cammie Smith Barnes <cammie@chromium.org>
Cr-Commit-Position: refs/heads/master@{#842385}