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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
commit26a029d407be480d791972afb5975cf62c9360a6 (patch)
treef435a8308119effd964b339f76abb83a57c29483 /testing/web-platform/tests/layout-instability/buffered-flag.html
parentInitial commit. (diff)
downloadfirefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz
firefox-26a029d407be480d791972afb5975cf62c9360a6.zip
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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diff --git a/testing/web-platform/tests/layout-instability/buffered-flag.html b/testing/web-platform/tests/layout-instability/buffered-flag.html
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+++ b/testing/web-platform/tests/layout-instability/buffered-flag.html
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+<!DOCTYPE HTML>
+<meta charset=utf-8>
+<title>Layout Instability: PerformanceObserver sees entries with buffered flag</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 => {
+ // First observer creates second in callback to ensure the entry has been dispatched by the time
+ // the second observer begins observing.
+ new PerformanceObserver(() => {
+ const endTime = performance.now();
+ // Second observer requires 'buffered: true' to see entries.
+ new PerformanceObserver(t.step_func(list => {
+ assert_equals(list.getEntries().length, 1);
+ const entry = list.getEntries()[0];
+ assert_equals(entry.entryType, "layout-shift");
+ assert_greater_than_equal(entry.startTime, startTime);
+ assert_less_than_equal(entry.startTime, endTime);
+ assert_equals(entry.duration, 0.0);
+ assert_equals(entry.value, computeExpectedScore(300 * (100 + 60), 60));
+ resolve();
+ })).observe({'type': 'layout-shift', buffered: true});
+ }).observe({type: 'layout-shift'});
+ // Modify the position of the div to cause a layout-shift entry.
+ document.getElementById('myDiv').style = "top: 60px";
+ });
+}, 'PerformanceObserver with buffered flag sees previous layout-shift entry.');
+</script>
+</body>