| <!DOCTYPE html> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <script src=/resources/testdriver.js></script> |
| <script src=/resources/testdriver-actions.js></script> |
| <script src=/resources/testdriver-vendor.js></script> |
| <style></style> |
| <!-- |
| Web-font styled text that gets resized after an interaction stops LCP |
| observation should not make a new LCP emission. |
| --> |
| <textarea id='input'></textarea> |
| <div class="test">LCP: Web Font Styled Text Resize</div> |
| <script> |
| function addCSSRules() { |
| styleSheet = document.styleSheets[0]; |
| fontRuleSet = "@font-face {\ |
| font-family: 'ADTestFaceInteraction';\ |
| src: url('/fonts/AD.woff');\ |
| font-display: swap;\ |
| }"; |
| fontAtRule = ".test {\ |
| font-family: 'ADTestFaceInteraction';\ |
| } "; |
| styleSheet.insertRule(fontRuleSet); |
| styleSheet.insertRule(fontAtRule); |
| } |
| |
| function LCPEntryList(t) { |
| return new Promise(resolve => { |
| let = lcpEntries = []; |
| new PerformanceObserver((entryList, observer) => { |
| lcpEntries = lcpEntries.concat(entryList.getEntries()); |
| if (lcpEntries) { |
| // Adding timeout to wait a bit more so that if there are more than |
| // expected LCP entries emitted, they can be observed. |
| t.step_timeout(() => { |
| resolve(lcpEntries); |
| observer.disconnect(); |
| }, 200); |
| } |
| }).observe({ type: 'largest-contentful-paint', buffered: true }); |
| }); |
| } |
| |
| promise_test(async t => { |
| await document.fonts.ready; |
| let system_font_size = document.getElementsByClassName('test')[0].offsetHeight; |
| |
| // Verify an LCP entry is emitted. |
| let entryList = await LCPEntryList(t); |
| assert_equals(entryList.length, 1, 'Text with system font should make a LCP emission.'); |
| |
| let lcpEntryBeforeInteraction = entryList[0]; |
| |
| // Add event listener so that CSS rule would be added after there's an |
| // input. |
| let inputElement = document.getElementById('input'); |
| inputElement.addEventListener('keydown', addCSSRules); |
| |
| // Send key as input. |
| await test_driver.send_keys(inputElement, 'k'); |
| |
| // Wait for web font to load. |
| await document.fonts.ready; |
| |
| // Verify web font is downloaded. |
| assert_own_property(window, 'PerformanceResourceTiming', "ResourceTiming not supported"); |
| let url = '/fonts/AD.woff'; |
| 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 ADTestFaceInteraction'), 'Font should be the web font added'); |
| |
| // Verify web font is applied. |
| let web_font_size = document.getElementsByClassName('test')[0].offsetHeight; |
| assert_not_equals(web_font_size, system_font_size, 'Web font swap should happen'); |
| |
| // Assert there is only 1 LCP entry, which verifies the added web font does |
| // not make a new LCP entry after an input. |
| entryList = await LCPEntryList(t); |
| assert_equals(entryList.length, 1, 'Text with system font should not make a LCP emission.'); |
| |
| // Verify the LCP entry is the same one emitted before interaction by |
| // asserting the size is the same. |
| assert_equals(lcpEntryBeforeInteraction.size, entryList[0].size, 'There should be only 1 LCP entry emitted.'); |
| |
| }, "LCP should be not updated if the web font styled text resize occurs after an interaction happens"); |
| </script> |