nested-containertiming-and-ignore-on-img.html

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This test has a WPT meta file that expects 1 subtest issues.
This WPT test may be referenced by the following Test IDs:
- /container-timing/tentative/nested-containertiming-and-ignore-on-img.html - WPT Dashboard Interop Dashboard

<!DOCTYPE HTML>

<meta charset=utf-8>

<title>Container Timing: an image with both containertiming and containertiming-ignore inside an outer containertiming root</title>

<body>

<style>

body {

  margin: 0;

</style>

<script src="/resources/testharness.js"></script>

<script src="/resources/testharnessreport.js"></script>

<script src="/container-timing/resources/container-timing-helpers.js"></script>

<script>

  let beforeRender;

  async_test(function (t) {

    assert_implements(window.PerformanceContainerTiming, "PerformanceContainerTiming is not implemented");

    const observer = new PerformanceObserver(

      t.step_func_done(function(entryList) {

        // Only one entry: the inner image root. The outer containertiming

        // root must NOT receive the paint because the image carries

        // containertiming-ignore which blocks upward propagation.

        assert_equals(entryList.getEntries().length, 1,

            'one entry expected for the image root, none for the outer root');

        const entry = entryList.getEntries()[0];

        checkContainerEntry(entry, 'image_ct', 'my_id', beforeRender);

        checkContainerIntersectionRect(entry, [0, 100, 0, 100])

        checkContainerSize(entry, 10000);

})

);

    observer.observe({entryTypes: ['container']});

    // Outer containertiming root.

    const outer = document.createElement('div');

    outer.setAttribute('containertiming', 'outer_ct');

    document.body.appendChild(outer);

    // Image that is itself a container timing root and has

    // containertiming-ignore set. The ignore must prevent the image's paint

    // from propagating to the outer containertiming root, but the image

    // itself must still report under its own root.

    const img = document.createElement('img');

    img.src = '/container-timing/resources/square100.png';

    img.setAttribute('containertiming', 'image_ct');

    img.setAttribute('containertiming-ignore', '');

    img.setAttribute('id', 'my_id');

    outer.appendChild(img);

    beforeRender = performance.now();

  }, 'Image with containertiming + containertiming-ignore inside outer containertiming reports under itself only.');

</script>

</body>