Need to propagate tallest unbreakable before forced breaks.

Even if there's a forced break inside the child added to the fragment builder, we need to propagate the tallest unbreakable block-size, to get column balancing right. This fixes an existing test, but I felt that we needed a test that more clearly illustrates this fix, so added that. The existing test still fails in legacy layout, but for a different reason (layout is correct, but outline painting order is wrong). Took the opportunity to rename PropagateBreak() to PropagateBreakInfo(), since this method doesn't only care about actual breaks. Also, no need to call this one if no block fragmentation is involved. Bug: 829028 Change-Id: Ie951817095267567b9fae578fd519b4ba76dc24c Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3231178 Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org> Commit-Queue: Morten Stenshorne <mstensho@chromium.org> Cr-Commit-Position: refs/heads/main@{#933116}
web-platform-tests · Oct 19, 2021 · 18e08e2 · 18e08e2
1 parent 4c956da
commit 18e08e2
Showing 1 changed file with 17 additions and 0 deletions.
diff --git a/css/css-multicol/multicol-fill-balance-016.html b/css/css-multicol/multicol-fill-balance-016.html
@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<link rel="author" title="Morten Stenshorne" href="mailto:mstensho@chromium.org">
+<link rel="help" href="https://www.w3.org/TR/css-multicol-1/#cf">
+<p>Test passes if there is a filled green square.</p>
+<div id="mc" style="columns:10; background:green;">
+  <div>
+    <div style="height:100px; contain:size;"></div>
+    <div style="break-before:column;"></div>
+  </div>
+</div>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script>
+  test(()=> {
+    assert_equals(mc.offsetHeight, 100);
+  });
+</script>