| <!DOCTYPE html> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <style> |
| @font-face { |
| font-family: 'ADTestFaceSwap'; |
| src: url('/fonts/AD.woff?pipe=trickle(d0.5)'); |
| font-display: swap; |
| } |
| |
| .test { |
| font-family: 'ADTestFaceSwap'; |
| } |
| |
| </style> |
| <!-- |
| Web-font styled 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">LCP: Web Font Styled Text Resize</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 ADTestFaceSwap'), '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 2ndLCP 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> |