With some refactoring of the relevant validation code.
Bug: dawn:520
Change-Id: Iedda0f7b1b67c20d3a88f2c4183dcc8eeae2096f
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/30742
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Kai Ninomiya <kainino@chromium.org>