[css-tables] Don't use internal layout structure when iterating all rows

third_party/WebKit/Source/core/layout/LayoutTableSection.h

 /*
  * 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, 2013 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 228 matching lines @@
     int calcBlockDirectionOuterBorder(BlockBorderSide) const;
     enum InlineBorderSide { BorderStart, BorderEnd };
     int calcInlineDirectionOuterBorder(InlineBorderSide) const;
     void recalcOuterBorder();
 
     int outerBorderBefore() const { return m_outerBorderBefore; }
     int outerBorderAfter() const { return m_outerBorderAfter; }
     int outerBorderStart() const { return m_outerBorderStart; }
     int outerBorderEnd() const { return m_outerBorderEnd; }
 
-    unsigned numRows() const { return m_grid.size(); }
+    unsigned numRows() const
+    {
+        DCHECK(!needsCellRecalc());
+        return m_grid.size();
+    }
     unsigned numEffectiveColumns() const;
 
     // recalcCells() is used when we are not sure about the section's structure
     // and want to do an expensive (but safe) reconstruction of m_grid from
     // scratch.
     // An example of this is inserting a new cell in the middle of an existing
     // row or removing a row.
     //
     // Accessing m_grid when m_needsCellRecalc is set is UNSAFE as pointers can
     // be left dangling. Thus care should be taken in the code to check
@@ skipping 142 matching lines @@
     bool m_hasMultipleCellLevels;
 
     LayoutUnit m_offsetForRepeatingHeader;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutTableSection, isTableSection());
 
 } // namespace blink
 
 #endif // LayoutTableSection_h