| <!DOCTYPE HTML> |
| <meta charset=utf-8> |
| <title>Element Timing: observe element with buffered flag</title> |
| <body> |
| <style> |
| body { |
| margin: 0; |
| } |
| </style> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <script src="resources/element-timing-helpers.js"></script> |
| <script> |
| async_test(t => { |
| assert_implements(window.PerformanceElementTiming, "PerformanceElementTiming is not implemented"); |
| const beforeRender = performance.now(); |
| const img = document.createElement('img'); |
| // Initial observer used to know when entry has been dispatched |
| new PerformanceObserver(() => { |
| // Second observer should require buffered flag to receive the already-dispatched entry. |
| new PerformanceObserver(t.step_func_done(entryList => { |
| assert_equals(entryList.getEntries().length, 1); |
| const entry = entryList.getEntries()[0]; |
| const pathname = window.location.origin + '/images/black-rectangle.png'; |
| checkElement(entry, pathname, 'my_image', 'my_id', beforeRender, document.getElementById('my_id')); |
| // Test that viewport size is at least 100, so element is fully visible. |
| assert_greater_than_equal(document.documentElement.clientWidth, 100, 'Width should be >= 100'); |
| assert_greater_than_equal(document.documentElement.clientHeight, 100, 'Height should be >= 100'); |
| |
| checkRect(entry, [0, 100, 0, 50]); |
| checkNaturalSize(entry, 100, 50); |
| })).observe({type: 'element', buffered: true}); |
| }).observe({type: 'element'}); |
| img.src = '/images/black-rectangle.png'; |
| img.setAttribute('elementtiming', 'my_image'); |
| img.setAttribute('id', 'my_id'); |
| document.body.appendChild(img); |
| }, 'Element Timing entries are observable via buffered flag.'); |
| </script> |
| </body> |