78 lines
3.2 KiB
HTML
78 lines
3.2 KiB
HTML
<!DOCTYPE HTML>
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<html>
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<head>
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<meta charset="utf-8">
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<meta name="viewport" content="width=device-width; initial-scale=1.0">
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<title>Scrolling doesn't cause extra SchedulePaint calls</title>
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<script src="/tests/SimpleTest/EventUtils.js"></script>
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<script type="application/javascript" src="apz_test_native_event_utils.js"></script>
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<script type="application/javascript" src="apz_test_utils.js"></script>
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<script src="/tests/SimpleTest/paint_listener.js"></script>
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<script type="application/javascript">
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async function test() {
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if (getPlatform() == "android") {
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return;
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}
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while (window.scrollY == 0) {
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// the scrollframe is not yet marked as APZ-scrollable. Mark it so before
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// continuing.
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window.scrollTo(0, 1000);
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await promiseApzFlushedRepaints();
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}
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window.synthesizeKey("KEY_ArrowDown");
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// This is really tricky. We want to check that during the main part of
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// scrolling after this we don't get any SchedulePaint calls. The way that we
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// test that is to use checkAndClearDisplayListState on the document element
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// to make sure it didn't have display list building ran for it. The
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// synthesizeKey calls above will end up in ScrollFrameHelper::ScrollBy,
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// which calls SchedulePaint in order to pass the scroll to the compositor to
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// perform. That SchedulePaint will result in display list building for the
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// document element, and that's okay, but we want to call
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// checkAndClearDisplayListState (to clear the display list building state)
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// right after that display list building, so that we can observe if any
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// display list building happens after it. That way that we do that is a rAF,
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// which runs immediately before painting, and then a setTimeout from the
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// rAF, which should run almost immediately after painting. Then we wait for
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// a scroll event, this scroll event is triggered by the compositor updating
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// the main thread scroll position. And here is where we finally get to what
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// we want to actually test. The original bug came about when the main
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// thread, while processing the repaint request from the compositor, called
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// SchedulePaint, and hence caused display list building. So we want to check
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// that the refresh driver tick after the scroll event does not do any
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// display list building. We again use a setTimeout from a rAF to run right
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// after the paint and check that there was no display list building.
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await new Promise(resolve => {
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window.requestAnimationFrame(() => {
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setTimeout(checkNoDisplayListRebuild, 0, resolve);
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});
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});
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}
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function checkNoDisplayListRebuild(resolve) {
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var utils = window.opener.SpecialPowers.getDOMWindowUtils(window);
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var elem = document.documentElement;
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utils.checkAndClearDisplayListState(elem);
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window.addEventListener("scroll", function () {
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window.requestAnimationFrame(() => {
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setTimeout(function() {
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is(utils.checkAndClearDisplayListState(elem), false, "Document element didn't get display list");
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resolve();
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},0);
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});
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}, {once: true});
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}
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waitUntilApzStable()
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.then(test)
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.then(subtestDone, subtestFailed);
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</script>
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</head>
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<body style="height: 5000px">
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<div style="height: 50px">spacer</div>
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<button id="b" style="width: 10px; height: 10px"></button>
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</body>
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</html>
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