Don't stretch margin: auto items in a vertical flexbox

Source/core/rendering/RenderBox.cpp

Index: Source/core/rendering/RenderBox.cpp
diff --git a/Source/core/rendering/RenderBox.cpp b/Source/core/rendering/RenderBox.cpp
index 747528e6a35f7bfebec806bbb570a3990b21849a..21a567302a7f3f696a005e02c1994ce950c2f2b5 100644
--- a/Source/core/rendering/RenderBox.cpp
+++ b/Source/core/rendering/RenderBox.cpp
@@ -2181,6 +2181,10 @@ LayoutUnit RenderBox::computeLogicalWidthInRegionUsing(SizeType widthType, Lengt
 static bool flexItemHasStretchAlignment(const RenderObject* flexitem)
 {
     RenderObject* parent = flexitem->parent();
+    // auto margins mean we don't stretch. Note that this function will only be used for
+    // widths, so we don't have to check marginBefore/marginAfter.

[ojan, 2013/05/24 22:39:09]

Instead of adding (or maybe in addition to) the extra "Note" section, how about
adding an ASSERT(parent()->style()->isColumnFlexDirection()); and renaming this
function to columnFlexItemHasStretchAlignment?

+    if (flexitem->style()->marginStart().isAuto() || flexitem->style()->marginEnd().isAuto())
+        return false;
     return flexitem->style()->alignSelf() == AlignStretch || (flexitem->style()->alignSelf() == AlignAuto && parent->style()->alignItems() == AlignStretch);
 }