Avoid unnecessary copies of AccessibilityChildrenVector

Source/modules/accessibility/AXTableRow.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 98 matching lines @@
         return 0;
 
     return headers[0].get();
 }
 
 void AXTableRow::headerObjectsForRow(AccessibilityChildrenVector& headers)
 {
     if (!m_renderer || !m_renderer->isTableRow())
         return;
 
-    AccessibilityChildrenVector rowChildren = children();
+    const AccessibilityChildrenVector& rowChildren = children();
     unsigned childrenCount = rowChildren.size();
     for (unsigned i = 0; i < childrenCount; i++) {
         AXObject* cell = rowChildren[i].get();
         if (!cell->isTableCell())
             continue;
 
         if (toAXTableCell(cell)->scanToDecideHeaderRole() == RowHeaderRole)
             headers.append(cell);
     }
 }
 
 } // namespace blink