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https://github.com/web-platform-tests/wpt
26 December 2018, 22:31:15 UTC
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Tip revision: a619744eead89c5105c98040bf77f11c40eaa311 authored by Geoffrey Sneddon on 09 October 2018, 17:34:30 UTC
Only run Windows CI for tools/ changes
Tip revision: a619744
first-contentful-paint.html 
<!DOCTYPE html>
<head>
<title>Performance Paint Timing Test: FP followed by FCP</title>
</head>
<body>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<div id="main"></div>
<div id="image"></div>

<script>
async_test(function (t) {
    const bufferedEntries = performance.getEntriesByType('paint');
    assert_equals(bufferedEntries.length, 0, "No paint entries yet");
    const div = document.createElement("div");
    div.style.width = "100px";
    div.style.height = "100px";
    div.style.backgroundColor = "red";
    div.style.color = "blue";
    document.getElementById("main").appendChild(div);
    function testPaintEntries() {
      const bufferedEntries = performance.getEntriesByType('paint');
      if (bufferedEntries.length < 1) {
        t.step_timeout(function() {
          testPaintEntries();
        }, 20);
        return;
      }
      t.step(function() {
        assert_equals(bufferedEntries.length, 1, "FP only.");
        assert_equals(bufferedEntries[0].entryType, "paint");
        assert_equals(bufferedEntries[0].name, "first-paint");
      });
      const img = document.createElement("IMG");
      img.src = "resources/circles.png";
      img.onload = function() {
        function secondTestPaintEntries() {
          const moreBufferedEntries = performance.getEntriesByType('paint');
          if (moreBufferedEntries.length < 2) {
            t.step_timeout(function() {
              secondTestPaintEntries();
            }, 20);
            return;
          }
          t.step(function() {
            assert_equals(moreBufferedEntries.length, 2, "FP and FCP.");
            assert_equals(moreBufferedEntries[0].entryType, "paint");
            assert_equals(moreBufferedEntries[0].name, "first-paint");
            const fpEntriesGotByName =
                performance.getEntriesByName('first-paint');
            assert_equals(fpEntriesGotByName.length, 1);
            assert_equals(moreBufferedEntries[0], fpEntriesGotByName[0]);
            assert_equals(moreBufferedEntries[1].entryType, "paint");
            assert_equals(moreBufferedEntries[1].name, "first-contentful-paint");
            const fcpEntriesGotByName =
                performance.getEntriesByName('first-contentful-paint');
            assert_equals(fcpEntriesGotByName.length, 1);
            assert_equals(moreBufferedEntries[1], fcpEntriesGotByName[0]);
            t.done();
          });
        }
        t.step(function() {
          secondTestPaintEntries();
        });
      };
      document.getElementById('image').appendChild(img);
    }
    t.step(function() {
      testPaintEntries();
    });
}, "First Paint triggered by non-contentful paint. Image load triggers First Contentful Paint.");
</script>
</body>
</html>
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