The functions are not used in the code but are useful during development
to try to see where race condition with the X server are.

BUG=angleproject:892

Change-Id: Ie1267e46ac251bd9ac62e2a146db68ad84644fb8
Reviewed-on: https://chromium-review.googlesource.com/271177Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Corentin Wallez <cwallez@chromium.org>