Content - 3610a57ec716c4c087caedc6aba0c132e98ded03 - e242f24/paint-timing/first-contentful-canvas.html

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Tip revision: 83be7773ed3e2df8c2f8625d11ec35358586e48c authored by Anne van Kesteren on 13 March 2018, 17:31:34 UTC
Improve HTMLAllCollection IDL

Tip revision: 83be777

first-contentful-canvas.html

<!DOCTYPE html>
<head>
<title>Performance Paint Timing Test: FCP due to canvas</title>
</head>
<body>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<canvas id="canvas" width="200" height="200" ></canvas>

<script>
async_test(function (t) {
    const canvas = document.getElementById("canvas");
    const context = canvas.getContext("2d");
    context.beginPath();
    context.moveTo(0,0);
    context.lineTo(300,150);
    context.stroke();
    function testPaintEntries() {
        const bufferedEntries = performance.getEntriesByType('paint');
        if (bufferedEntries.length < 2) {
            t.step_timeout(function() {
                testPaintEntries();
            }, 20);
            return;
        }
        t.step(function() {
            assert_equals(bufferedEntries.length, 2, "There should be two paint timing instances.");
            assert_equals(bufferedEntries[0].entryType, "paint");
            assert_equals(bufferedEntries[0].name, "first-paint");
            assert_equals(bufferedEntries[1].entryType, "paint");
            assert_equals(bufferedEntries[1].name, "first-contentful-paint");
            t.done();
        });
    };
    t.step(function() {
        testPaintEntries();
    });
}, "First contentful paint fires due to canvas render.");
</script>
</body>
</html>

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