Bug 1551895 [wpt PR 16817] - [LayoutNG] Don't force legacy layout on ::first-letter pseudos., a=testonly

Automatic update from web-platform-tests [LayoutNG] Don't force legacy layout on ::first-letter pseudos. Due to the complicated behavior of ::first-letter elements, where the placement of the ::first-letter DOM node in the DOM tree doesn't correspond with where we place the LayoutObject in the layout tree, it's tricky to figure out whether it's part of a subtree that requires us to force legacy layout or not. So just skip checking. The ::first-letter element itself can never force legacy layout on its own, so we'll just do whatever the parent layout object does. Solution developed together with futhark@chromium.org Bug: 962090 Change-Id: Ie112561bbd58c0c6f822f500247dbbaa1c8a8118 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1611602 Commit-Queue: Morten Stenshorne <mstensho@chromium.org> Reviewed-by: Rune Lillesveen <futhark@chromium.org> Cr-Commit-Position: refs/heads/master@{#659529} -- wp5At-commits: c62b2bd41d8e00a677d7ef56fecda804f0d4fe39 wpt-pr: 16817
2019-06-13 10:19:32 +00:00 · 2019-06-13 10:19:32 +00:00 · 83c056b321
--- a/testing/web-platform/tests/editing/run/first-letter-crossing-engine-boundary-crash.html
+++ b/testing/web-platform/tests/editing/run/first-letter-crossing-engine-boundary-crash.html
@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<link rel="author" title="Morten Stenshorne" href="mailto:mstensho@chromium.org">
+<link rel="help" href="http://crbug.com/962090">
+<style>
+  #container::first-letter { background:blue; }
+</style>
+<div id="container">
+  <div id="edit" style="overflow:hidden;" contenteditable>xx</div>
+  <div id="elm" style="display:none;">PASS</div>
+</div>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script>
+  document.body.offsetTop;
+  elm.style.display = "initial";
+  test(()=>{}, "No crash or DCHECK failure");
+</script>