images-repeated-resource.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:
- /element-timing/images-repeated-resource.html - WPT Dashboard Interop Dashboard

<!DOCTYPE HTML>

<meta charset=utf-8>

<title>Element Timing: observe elements with the same resource</title>

<body>

<style>

body {

  margin: 0;

</style>

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

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

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

<script>

  let beforeRender;

  let numEntries = 0;

  let loadTime1;

  let loadTime2;

  let renderTime1;

  let renderTime2;

  let img;

  let img2;

  async_test(function (t) {

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

    const observer = new PerformanceObserver(

      t.step_func(function(entryList) {

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

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

        const pathname = window.location.origin + '/element-timing/resources/square100.png';

        // Easier to check the |element| attribute here since element ID is the same for both images.

        checkElement(entry, pathname, entry.identifier, 'image_id', beforeRender, null);

        checkNaturalSize(entry, 100, 100);

        if (entry.identifier === 'my_image') {

          ++numEntries;

          loadTime1 = entry.loadTime;

          renderTime1 = entry.renderTime;

          assert_equals(entry.element, img);

          img2 = document.createElement('img');

          img2.src = 'resources/square100.png';

          img2.setAttribute('elementtiming', 'my_image2');

          img2.setAttribute('id', 'image_id');

          document.body.appendChild(img2);

          beforeRender = performance.now();

        else if (entry.identifier === 'my_image2') {

          ++numEntries;

          loadTime2 = entry.loadTime;

          renderTime2 = entry.renderTime;

          assert_equals(entry.element, img2);

        if (numEntries == 2) {

          assert_greater_than(loadTime2, loadTime1, 'Second image loads after first.');

          assert_greater_than(renderTime2, renderTime1, 'Second image renders after first');

          t.done();

})

);

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

    // We add the images during onload to be sure that the observer is registered

    // in time for it to observe the element timing.

    window.onload = () => {

      // Add image of width and height equal to 100.

      img = document.createElement('img');

      img.src = 'resources/square100.png';

      img.setAttribute('elementtiming', 'my_image');

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

      document.body.appendChild(img);

      beforeRender = performance.now();

};

  }, 'Elements with elementtiming and same src are observable.');

</script>

</body>