Begin tracking why layout is invalidated

Source/core/layout/LayoutTableCol.cpp

 /*
  * Copyright (C) 1997 Martin Jones (mjones@kde.org)
  *           (C) 1997 Torben Weis (weis@kde.org)
  *           (C) 1998 Waldo Bastian (bastian@kde.org)
  *           (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 63 matching lines @@
 {
     unsigned oldSpan = m_span;
     Node* n = node();
     if (isHTMLTableColElement(n)) {
         HTMLTableColElement& tc = toHTMLTableColElement(*n);
         m_span = tc.span();
     } else {
         m_span = !(style() && style()->display() == TABLE_COLUMN_GROUP);
     }
     if (m_span != oldSpan && style() && parent())
-        setNeedsLayoutAndPrefWidthsRecalcAndFullPaintInvalidation();
+        setNeedsLayoutAndPrefWidthsRecalcAndFullPaintInvalidation(LayoutInvalidationReason::Unknown);

[esprehn, 2015/03/23 20:19:44]

AttributeChanged ? This is when the span attr changes.

 }
 
 void LayoutTableCol::insertedIntoTree()
 {
     LayoutBox::insertedIntoTree();
     table()->addColumn(this);
 }
 
 void LayoutTableCol::willBeRemovedFromTree()
 {
@@ skipping 94 matching lines @@
     return style()->borderStart();
 }
 
 const BorderValue& LayoutTableCol::borderAdjoiningCellAfter(const LayoutTableCell* cell) const
 {
     ASSERT_UNUSED(cell, table()->colElement(cell->col() - 1) == this);
     return style()->borderEnd();
 }
 
 }