<!DOCTYPE html> <script src="/resources/testharness.js"></script> <script src="/resources/testharnessreport.js"></script> <style> @font-face { font-family: 'ADTestFaceSwapSubnode'; src: url('/fonts/AD.woff?pipe=trickle(d0.5)'); font-display: swap; } .test { font-family: 'ADTestFaceSwapSubnode'; } </style> <!-- Web-font styled subnode text that gets resized during swap period should make a LCP emission if the new size is larger than the existing LCP element size. --> <div class="test"> <span>LCP: Web Font Styled Text Resize</span> </div> <script> function LCPEntryList() { return new Promise(resolve => { let = lcpEntries = []; new PerformanceObserver((entryList, observer) => { lcpEntries = lcpEntries.concat(entryList.getEntries()); if (lcpEntries.length == 2) { resolve(lcpEntries); observer.disconnect(); } }).observe({ type: 'largest-contentful-paint', buffered: true }); }); } promise_test(async t => { await document.fonts.ready; // Verify web font is downloaded. assert_own_property(window, 'PerformanceResourceTiming', "ResourceTiming not supported"); let url = '/fonts/AD.woff?pipe=trickle(d0.5)'; var absoluteURL = new URL(url, location.href).href; assert_equals(performance.getEntriesByName(absoluteURL).length, 1, 'Web font\ should be downloaded'); // Verify web font is available. assert_true(document.fonts.check('16px ADTestFaceSwapSubnode'), 'Font should be the web font added'); let entryList = await LCPEntryList(); // Verify there are 2 LCP entries emitted. assert_equals(entryList.length, 2, 'There should be 2 LCP entries. The 1st one corresponds to the system font and the 2nd the web font.') // Verify the size of 2nd LCP entry is larger than that of the 1st one. assert_greater_than(entryList[1].size, entryList[0].size, 'The size of 2nd LCP entry should be larger than that of the 1st one.'); }, "LCP should be updated if the web font styled text resizes to be larger during the swap period"); </script>