mozilla-central/testing/web-platform/tests/paint-timing/with-first-paint/sibling-painting-first-image.html

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Test Info: Warnings

<!DOCTYPE html>
<body>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<!-- This iframe will have a sibling that paints, we want to ensure it does not detect that paint. -->
<iframe id="listening-iframe" src="../resources/subframe-sending-paint.html"></iframe>
<script>
setup({"hide_test_state": true});
var entriesExpectToReceive = [
{
'entryType': 'paint',
'name': 'first-paint'
},
{
'entryType': 'paint',
'name': 'first-contentful-paint'
}
];
async_test(function (t) {
assert_implements(window.PerformancePaintTiming, "Paint Timing isn't supported.");
let paintingIframeHasDispatchedEntries = false;
window.addEventListener('message', t.step_func(e => {
if (!paintingIframeHasDispatchedEntries) {
// Check paint-timing entries from the painting iframe.
for (let i = 0; i < entriesExpectToReceive.length; i++) {
if (entriesExpectToReceive[i].entryType == e.data.entryType &&
entriesExpectToReceive[i].name == e.data.name) {
entriesExpectToReceive.splice(i, 1);
break;
}
}
if (entriesExpectToReceive.length == 0) {
paintingIframeHasDispatchedEntries = true;
// Ask the listening iframe to send its paint-timing entries.
document.getElementById('listening-iframe').
contentWindow.postMessage('', '*');
}
return;
}
// Check the paint-timing entries from the listening iframe.
assert_equals(e.data, '0');
// Check that current frame receives first-paint but not first-contentful-paint.
const bufferedEntries = performance.getEntriesByType('paint');
assert_equals(bufferedEntries.length, 1);
assert_equals(bufferedEntries[0].entryType, 'paint');
assert_equals(bufferedEntries[0].name, 'first-paint');
t.done();
}));
}, 'Frame ignores paint-timing events fired from sibling frame.');
</script>
<!-- This iframe is where all of the painting occurs. -->
<iframe id="painting-iframe" src="../resources/subframe-painting.html"></iframe>
</body>
</html>