Check for buffer under/over run in table cell painting

Source/core/layout/LayoutTableSection.h

Index: Source/core/layout/LayoutTableSection.h
diff --git a/Source/core/layout/LayoutTableSection.h b/Source/core/layout/LayoutTableSection.h
index 8e8d7e51432c5c4586acb8445c945609ecc2444c..e950ee7d95aaeebf58bc5fc475354e9d3d653d58 100644
--- a/Source/core/layout/LayoutTableSection.h
+++ b/Source/core/layout/LayoutTableSection.h
@@ -56,6 +56,8 @@ public:
     void decreaseStart() { --m_start; }
     void increaseEnd() { ++m_end; }
 
+    void ensureConsistency(const unsigned);
+
 private:
     unsigned m_start;
     unsigned m_end;