Add EGL validation helper files and move some validation to them. BUG=angle:658 Change-Id: Id560268a280f2fa7d75a7d0727dac830fe8de9f1 Reviewed-on: https://chromium-review.googlesource.com/242034 Reviewed-by: Kenneth Russell <kbr@chromium.org> Reviewed-by: Brandon Jones <bajones@chromium.org> Tested-by: Geoff Lang <geofflang@chromium.org>