WindowServices: moves a couple more interfaces to OnceCallback

BUG=714018
TEST=none

Change-Id: I6c8f6644a55fecccadf6257cd908404ca5bb7250
Reviewed-on: https://chromium-review.googlesource.com/947807
Commit-Queue: Scott Violet <sky@chromium.org>
Reviewed-by: Michael Wasserman <msw@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541039}
15 files changed