[Masonry] Use max-content for stacking axis min-content

alisonmaher · chromium-wpt-export-bot · commit 82c4b7e40bb1 · 2025-11-03T09:32:52.000-08:00
Per the proposal in [1], "Have the min-content size of the stacking axis of a masonry container be the same as its max-content size (same as the "stacking axis" of block layout)." This CL implements this proposal and updates the expectation of the test that kicked of this issue originally. It also fixes crashes in a few tests where orthogonal items in a row masonry had a larger min-content size than max-content size, leading to a check that expected the container min-content to be <= to the max-content size. [1] w3c/csswg-drafts#12843 (comment) Bug: 343257585 Change-Id: I35eab974b3518968ee4d686dfbc0adafa43f9a43 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7107410 Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org> Commit-Queue: Alison Maher <almaher@microsoft.com> Cr-Commit-Position: refs/heads/main@{#1539388}
diff --git a/css/css-grid/masonry/tentative/item-placement/row-auto-placement-min-content-ref.html b/css/css-grid/masonry/tentative/item-placement/row-auto-placement-min-content-ref.html
@@ -10,20 +10,14 @@
 .grid {
     display: grid;
     grid-template-rows: 15px auto auto;
-    width: min-content;
+    width: max-content;
+    background: gray;
     align-items: start;
     padding: 10px;
 }
-
-#gray-bg {
-    background: gray;
-    position: absolute;
-    z-index: -1;
-}
 </style>
 <body>
   <p>Ensure that masonry containers are sized correctly under min-content constraints even if the items do not have the min-content style.</p>
-  <div id="gray-bg"></div>
   <div id="shown-items" class="grid">
     <div style="background: lightskyblue; width: max-content; grid-row: 1; grid-column: 1;">
         Number 1
