Adding a few setTimeouts to the utility function

[thejohnjansen]

The timing in these tests is just a little of when these tests are automated. This is meant to address: #25023

[stephenmcgruer]

So knowing nothing about how the tests work, if the goal is to wait for the callback from the IntersectionObserver before checking things, would a promise-based test be useful? E.g. something like:

promise_test(async t => {
  let entries;
  let observerPromise = new Promise(resolve => {
    let observer = new IntersectionObserver(function(changes) {
        entries = changes;
        resolve();
    });
  });
  // do some stuff
  await observerPromise;
  // verify entries
}, 'my test');

But perhaps there is some complexity in needing to wait for multiple calls to the changes function or something like that?

Generally speaking, adding timeouts like this is only going to make a test flaky (particularly since they seem quite arbitrary in this diff).

Hopefully @szager-chromium can chime in, however, as someone who knows IntersectionObserver wayyyyyy better than me :)

[thejohnjansen]

Thanks for the comment @stephenmcgruer I pushed new changes to make it simpler before I read your comment, don't want you to think I was ignoring you. I'll look forward to hearing from @szager-chromium as well. For these tests I think the complexity is in the requestAnimationFrame, but I don't know exactly how these work either.

[thejohnjansen]

Would it be possible to merge this and discuss the possibility of a re-write to promises with the Working Group? I don't like that wpt.fyi shows inaccurate test results for this. I'm sure there are probably other places as well that I am going to start looking into.

I just remembered about the 2way sync that was enabled some time ago with chromium. If it makes more sense, I could make this change in the chromium repo.

[szager-chromium]

I made a comment on the bug -- tl;dr I am pretty strongly against landing this change.