Consider removing css/css-view-transitions/no-painting-while-render-blocked.html

[vmpstr]

Test List

https://wpt.fyi/results/css/css-view-transitions/no-painting-while-render-blocked.html

Rationale

This test uses a takeScreenshot within a callback while the page is not producing frames. I don't believe this is a valid way to test what is currently on the screen, since takeScreenshot AFAIK removes the reftest-wait and relies on a frame being produced (which is the very thing being tested not happening).

From the looks of it, all browsers are failing this test.

I propose removing it.

/cc @mattwoodrow @nt1m

[foolip]

Can the test be modified to match the actual behavior, or is there really nothing useful that can be tested while the page is not producing frames?

[vmpstr]

I think there is a fundamental limitation to what we can test here. In Chromium we do have tests that verify that content isn't presented/updated while we're render blocked, but they are not WPTs or web tests, but rather a variant of unittest/browsertest.

I don't know of a way to query "what is currently on screen" without actually producing a frame in a WPT environment.

[nt1m]

I have the same initial reaction as @foolip, but I'd be fine dropping if there's no way to fix these tests.

[jgraham]

CC @BorisChiou

[BorisChiou]

I'm OK to drop this if nothing we can do to fix this test, given that the current test doesn't use a valid way to verify this feature.

(Note that Gecko is still working on rendering suppression, but yes I agree with this so it's fine to me to drop it.)