Move Windows-only include into #if

Bug: 242216
Change-Id: I0095ba420cbf63c2b5d8e135b292b7814d31839c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3445099


Reviewed-by: Ken Buchanan <kenrb@chromium.org>
Commit-Queue: Ken Buchanan <kenrb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#968350}