| <!DOCTYPE HTML> |
| <meta charset=utf-8> |
| <title>Largest Contentful Paint: src change triggers new entry.</title> |
| <body> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <img src='/images/blue.png' id='image_id'/> |
| <script> |
| async_test(function (t) { |
| if (!window.LargestContentfulPaint) { |
| assert_unreached("LargestContentfulPaint is not implemented"); |
| } |
| let beforeRender = performance.now(); |
| let firstCallback = true; |
| const observer = new PerformanceObserver( |
| t.step_func_done(function(entryList) { |
| assert_equals(entryList.getEntries().length, 1); |
| const entry = entryList.getEntries()[0]; |
| assert_equals(entry.entryType, 'largest-contentful-paint'); |
| assert_greater_than_equal(entry.renderTime, beforeRender, |
| 'The rendering timestamp should occur after script starts running.'); |
| assert_greater_than_equal(performance.now(), entry.renderTime, |
| 'The rendering timestamp should occur before the entry is dispatched to the observer.'); |
| assert_equals(entry.startTime, entry.renderTime, 'startTime should equal renderTime'); |
| assert_equals(entry.duration, 0); |
| if (firstCallback) { |
| // blue.png is 133 x 106. |
| assert_equals(entry.size, 14098); |
| assert_equals(entry.id, 'image_id'); |
| const pathname = window.location.origin + '/images/blue.png'; |
| assert_equals(entry.url, pathname); |
| |
| // Set the src to trigger another entry. |
| const img = document.getElementById('image_id'); |
| img.src = '/images/black-rectangle.png'; |
| beforeRender = performance.now(); |
| firstCallback =false; |
| return; |
| } |
| // black-rectangle.png is 100 x 50. |
| assert_equals(entry.size, 5000); |
| assert_equals(entry.id, 'image_id'); |
| const pathname = window.location.origin + '/images/black-rectangle.png'; |
| assert_equals(entry.url, pathname); |
| }) |
| ); |
| observer.observe({type: 'largest-contentful-paint', buffered: true}); |
| }, 'Largest Contentful Paint: changing src causes a new entry to be dispatched.'); |
| </script> |
| </body> |
