[FFC] ContentDistribution::Default is "align-content" initial value o…

…nly when position is ContentPosition::Normal

https://bugs.webkit.org/show_bug.cgi?id=259625

Reviewed by Antti Koivisto.

Need to check StyleContentAlignmentData's distribution and position for initial value (which is align-content: stretch).

* Source/WebCore/layout/formattingContexts/flex/FlexLayout.cpp:
(WebCore::Layout::FlexLayout::stretchFlexLines const):

Canonical link: https://commits.webkit.org/266473@main

Source/WebCore/layout/formattingContexts/flex/FlexLayout.cpp

@@ -502,8 +502,10 @@ void FlexLayout::stretchFlexLines(LinesCrossSizeList& flexLinesCrossSizeList, si
     // If the flex container has a definite cross size, align-content is stretch, and the sum of the flex lines' cross sizes is less than the flex container's inner cross size,
     // increase the cross size of each flex line by equal amounts such that the sum of their cross sizes exactly equals the flex container's inner cross size.
     auto linesMayStretch = [&] {
-        auto alignContent = flexContainerStyle().alignContent().distribution();
-        return alignContent == ContentDistribution::Stretch || alignContent == ContentDistribution::Default;
+        auto alignContent = flexContainerStyle().alignContent();
+        if (alignContent.distribution() == ContentDistribution::Stretch)
+            return true;
+        return alignContent.distribution() == ContentDistribution::Default && alignContent.position() == ContentPosition::Normal;
     };
     if (!linesMayStretch() || !crossAxis.definiteSize)
         return;