Previously the OS window was deleted before the EGL window surface which
caused the GLX window to be deleted after its X window was deleted. All
this was invalid and resulted in a crash.

BUG=angleproject:892

Change-Id: I394795b6ebce947ad7eeab9a70ad5f80fcd89241
Reviewed-on: https://chromium-review.googlesource.com/273055Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Corentin Wallez <cwallez@chromium.org>