Bug 1557365 [wpt PR 16859] - [LayoutNG] Only reset a legacy cached result if OOF-positioned., a=testonly

bfgeek · jgraham · commit 574604586f1d · 2019-06-19T11:05:28.000-07:00
Automatic update from web-platform-tests [LayoutNG] Only reset a legacy cached result if OOF-positioned. We had an issue with our simplified layout algorithm + relayout boundary roots. For this to trigger we needed a (legacy) layout object to be marked for simplified layout which was also a relayout boundary root. During LocalFrameView::PerformLayout, LayoutBox::UpdateLayout would run on the legacy LayoutBox, and during LayoutBox::UpdateAfterLayout, this would clear the LayoutBox::cached_layout_result_. During another relayout boundary layout, we'd trigger simplified layout for an NG node. This expects that there is always a cached layout result associated with a box. However this now wasn't the case, as the child had previously cleared it, within LayoutBox::UpdateAfterLayout. The guard inside LayoutBox::UpdateAfterLayout was designed to protect against OOF-positioned nodes changing their layout parent, this modifies that check do only clear the layout result of OOF-positioned legacy layout objects. Bug: 963387, 963433, 963620 Change-Id: Ice1202bdb939689e26e24a8690a52e7d7e82ecbc Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1614082 Reviewed-by: Aleks Totic <atotic@chromium.org> Commit-Queue: Ian Kilpatrick <ikilpatrick@chromium.org> Cr-Commit-Position: refs/heads/master@{#660166} -- wp5At-commits: c40cd30b2d4d686325f3b00403c1c3d0314219e3 wpt-pr: 16859
diff --git a/testing/web-platform/tests/css/css-position/position-absolute-dynamic-relayout-001.html b/testing/web-platform/tests/css/css-position/position-absolute-dynamic-relayout-001.html
@@ -0,0 +1,22 @@
+<!DOCTYPE html>
+<html class='reftest-wait'>
+<link rel="match" href="../reference/ref-filled-green-100px-square-only.html">
+<link rel="help" href="https://www.w3.org/TR/css-position-3/" />
+<meta name="assert" content="This test checks that a dynamic change in constraints does not crash the renderer."/>
+<script src="/common/reftest-wait.js"></script>
+<p>Test passes if there is a filled green square.</p>
+<div style="display: flex; width: 100px; height: 100px; overflow: hidden; position: relative;"> <!-- relayout boundary -->
+  <div style="position: relative;">
+    <div style="display: flex; position: relative; width: 100px; height: 50px; overflow: hidden;"> <!-- relayout boundary -->
+      <div id="target1" style="position: absolute; width: 10px; height: 50px; background: green;"></div>
+    </div>
+    <div id="target2" style="position: absolute; width: 10px; height: 50px; background: green;"></div>
+  </div>
+</div>
+<script>
+document.body.offsetTop;
+target2.style.width = '100px';
+target1.style.width = '100px';
+document.body.offsetTop;
+takeScreenshot();
+</script>
