<!DOCTYPE html>
<html>
<title>Makes sure that preloaded resources reduce connection time to zero</title>
<meta name="timeout" content="long">
<meta name="pac" content="/common/proxy-all.sub.pac">
<script src="/common/utils.js"></script>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<body>
<script>
const FAKE_PORT = 30303;
promise_test(async t => {
const fake_remote_origin = `http://${token()}.wpt:${FAKE_PORT}`;
const link = document.createElement('link');
link.rel = "preconnect";
link.href = fake_remote_origin;
document.head.appendChild(link);
await new Promise(r => t.step_timeout(r, 1000));
const url = `${fake_remote_origin}/images/smiley.png`;
const entryPromise = new Promise(resolve => {
new PerformanceObserver(list => {
const entries = list.getEntriesByName(url);
if (entries.length)
resolve(entries[0]);
}).observe({type: "resource"});
});
const img = document.createElement('img');
img.src = url;
document.body.appendChild(img);
const entry = await entryPromise;
assert_equals(entry.domainLookupStart, entry.domainLookupEnd);
assert_equals(entry.domainLookupStart, entry.connectStart);
assert_equals(entry.domainLookupStart, entry.connectEnd);
}, "Test that preconnect reduces connection time to zero");
</script>
</body>
</html>
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