Propagate NS_FRAME_CONTAINS_RELATIVE_BSIZE from inner scrolled frame to outer scroll frame.
Differential Revision: https://phabricator.services.mozilla.com/D130813
bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1739048
gecko-commit: 0bff7509335898a6811084aef05a468fb6c2df11
gecko-reviewers: dholbert
diff --git a/css/css-flexbox/percentage-heights-019.html b/css/css-flexbox/percentage-heights-019.html
new file mode 100644
index 0000000..4cc714c
--- /dev/null
+++ b/css/css-flexbox/percentage-heights-019.html
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+<!DOCTYPE html>
+<html>
+ <meta charset="utf-8">
+ <title>CSS Flexbox Test: Test the percentage resolution of a child in a flex item that has an indefinite main size</title>
+ <link rel="author" title="Ting-Yu Lin" href="mailto:tlin@mozilla.com">
+ <link rel="author" title="Mozilla" href="https://www.mozilla.org/">
+ <link rel="help" href="https://drafts.csswg.org/css-flexbox-1/#definite-sizes">
+ <link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1739048">
+ <link rel="match" href="../reference/ref-filled-green-100px-square.xht">
+ <meta name="assert" content="Per 9.8.4, once the outer flex container's cross size has been determined, the inner flex container's main size is considered definite. Then per 9.8.1, the item's post-flexing main size is also treated as definite. Therefore, in the final layout, the child's percentage block-size should be treated as resolvable and should be honored.">
+
+ <style>
+ .outer {
+ display: flex;
+ }
+
+ .inner {
+ display: flex;
+ flex-direction: column;
+ inline-size: 100px;
+ }
+
+ .item {
+ overflow: hidden; /* This is essential to reproduce the bug. */
+ min-block-size: 100px;
+ background: red;
+ }
+
+ .child {
+ block-size: 100%;
+ background: green;
+ }
+ </style>
+
+ <p>Test passes if there is a filled green square and <strong>no red</strong>.</p>
+
+ <div class="outer">
+ <div class="inner">
+ <div class="item">
+ <div class="child"></div>
+ </div>
+ </div>
+ </div>
+</html>
