Table's columns and rows should not be modified outside.

Source/modules/accessibility/AXTable.cpp

 /*
  * Copyright (C) 2008 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 431 matching lines @@
     if (m_headerContainer)
         return m_headerContainer.get();
 
     AXMockObject* tableHeader = toAXMockObject(axObjectCache()->getOrCreate(TableHeaderContainerRole));
     tableHeader->setParent(this);
 
     m_headerContainer = tableHeader;
     return m_headerContainer.get();
 }
 
-AXObject::AccessibilityChildrenVector& AXTable::columns()
+const AXObject::AccessibilityChildrenVector& AXTable::columns()
 {
     updateChildrenIfNecessary();
 
     return m_columns;
 }
 
-AXObject::AccessibilityChildrenVector& AXTable::rows()
+const AXObject::AccessibilityChildrenVector& AXTable::rows()
 {
     updateChildrenIfNecessary();
 
     return m_rows;
 }
 
 void AXTable::columnHeaders(AccessibilityChildrenVector& headers)
 {
     if (!m_renderer)
         return;
@@ skipping 117 matching lines @@
     }
 
     // try the standard
     if (title.isEmpty())
         title = AXRenderObject::title();
 
     return title;
 }
 
 } // namespace blink