Support :user-valid/:user-invalid on multifield inputs
This patch makes :user-valid and :user-invalid start working on inputs
with type date, datetime-local, and time.
I matched the webkit behavior for when to start matching in response to
keyboard input, and added a separate tentative test for that behavior.
Fixed: 328674226
Change-Id: If3c394e43043a0b3d27eac22d0671c6b45b82bc6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5463293
Reviewed-by: Di Zhang dizhangg@chromium.org
Commit-Queue: Joey Arhar jarhar@chromium.org
Cr-Commit-Position: refs/heads/main@{#1294002}