The span of a table-column or table-column-group should never be 0.

Source/core/layout/LayoutTableCol.cpp

Index: Source/core/layout/LayoutTableCol.cpp
diff --git a/Source/core/layout/LayoutTableCol.cpp b/Source/core/layout/LayoutTableCol.cpp
index 37c07f4dcdf6b3e376d68f509b2b58927852c371..73cf46dd452d94d3a96f7b9e5add71f4f5957fa1 100644
--- a/Source/core/layout/LayoutTableCol.cpp
+++ b/Source/core/layout/LayoutTableCol.cpp
@@ -78,7 +78,7 @@ void LayoutTableCol::updateFromElement()
         HTMLTableColElement& tc = toHTMLTableColElement(*n);
         m_span = tc.span();
     } else {
-        m_span = !(style() && style()->display() == TABLE_COLUMN_GROUP);

[leviw_travelin_and_unemployed, 2015/05/29 17:07:12]

This was just weird to begin with!

+        m_span = 1;
     }
     if (m_span != oldSpan && style() && parent())
         setNeedsLayoutAndPrefWidthsRecalcAndFullPaintInvalidation(LayoutInvalidationReason::AttributeChanged);