Add missing includes of waitable_event.h

Forward declarations were used when possible in headers

Bug: 1300573
Change-Id: Id7b2a428fa0f92eeacf974e0159644fa7299e9d8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3528197
Reviewed-by: Lei Zhang <thestig@chromium.org>
Owners-Override: Lei Zhang <thestig@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/main@{#982074}
NOKEYCHECK=True
GitOrigin-RevId: 10242c1163d550aa39472c2a2199f4e3ef3dde99
1 file changed