forked from mirrors/gecko-dev
7fcdc5f656
Automatic update from web-platform-tests Skip layout shift tracking for more invisible elements Besides the current conditions, e.g. visibility:hidden, opacity:0 (which is checked in PaintInvalidator instead of LayoutShiftTracker) etc., also ignore the following invisible elements: - For texts: - if the font is not renderable - if the text contains all whitespaces - For blocks: - if it doesn't have any decorations, and doesn't have any children. For performance and to reduce risk of false-negative of layout shift tracking, the conditions are kept simple. If a developer still get unexpected layout shift for invisible elements, we can suggest adding visibility:hidden to the element to explicitly disable layout shift tracking on the element. See https://ct.skia.org/results/cluster-telemetry/tasks/chromium_perf_runs/wangxianzhu-ChromiumPerf-5677/html/index.html for the change of overall CLS score with this CL. Bug: 1099350 Change-Id: Ib7e89e0331663572d1eef511976556e8b2a96a96 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2743811 Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org> Reviewed-by: Steve Kobes <skobes@chromium.org> Reviewed-by: Nicolás Peña Moreno <npm@chromium.org> Cr-Commit-Position: refs/heads/master@{#862593} -- wpt-commits: 48e5e3c75c9d0df0b18ee7628a98bbc85250eedd wpt-pr: 28030
45 lines
2 KiB
HTML
45 lines
2 KiB
HTML
<!DOCTYPE HTML>
|
|
<meta charset=utf-8>
|
|
<title>Layout Instability entries are not available via the performance timeline</title>
|
|
<body>
|
|
<style>
|
|
#myDiv { position: relative; width: 300px; height: 100px; background: blue; }
|
|
</style>
|
|
<div id='myDiv'></div>
|
|
<script src="/resources/testharness.js"></script>
|
|
<script src="/resources/testharnessreport.js"></script>
|
|
<script src="resources/util.js"></script>
|
|
<script>
|
|
promise_test(async t => {
|
|
assert_implements(window.LayoutShift, 'Layout Instability is not supported.');
|
|
// Wait for the initial render to complete.
|
|
await waitForAnimationFrames(2);
|
|
|
|
const startTime = performance.now();
|
|
return new Promise(resolve => {
|
|
new PerformanceObserver(t.step_func(list => {
|
|
const endTime = performance.now();
|
|
assert_equals(list.getEntries().length, 1);
|
|
const entry = list.getEntries()[0];
|
|
assert_equals(entry.entryType, "layout-shift");
|
|
assert_equals(entry.name, "");
|
|
assert_greater_than_equal(entry.startTime, startTime);
|
|
assert_less_than_equal(entry.startTime, endTime);
|
|
assert_equals(entry.duration, 0.0);
|
|
// The layout shift value should be:
|
|
// 300 * (100 + 60) * (60 / maxDimension) / viewport size.
|
|
assert_equals(entry.value, computeExpectedScore(300 * (100 + 60), 60));
|
|
|
|
// The entry should not be available via getEntries* methods.
|
|
assert_equals(performance.getEntriesByType('layout-shift').length, 0, 'getEntriesByType should have no layout-shift entries');
|
|
assert_equals(performance.getEntriesByName('', 'layout-shift').length, 0, 'getEntriesByName should have no layout-shift entries');
|
|
assert_equals(performance.getEntries().filter(e => e.entryType === 'layout-shift').length, 0, 'getEntries should have no layout-shift entries');
|
|
resolve();
|
|
})).observe({type: 'layout-shift'});
|
|
// Modify the position of the div.
|
|
document.getElementById('myDiv').style = "top: 60px";
|
|
});
|
|
}, 'Layout shift before onload is not buffered into the performance timeline.');
|
|
</script>
|
|
|
|
</body>
|