Remove some redundant code from accessibility table headers

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 85 matching lines @@
 {
     AXObject* parent = parentObjectUnignored();
     if (!parent || !parent->isAXTable())
         return 0;
 
     return parent;
 }
 
 AXObject* AXTableRow::headerObject()
 {
-    if (!m_renderer || !m_renderer->isTableRow())
+    AccessibilityChildrenVector headers;
+    headerObjectsForRow(headers);
+    if (!headers.size())
         return 0;
 
-    AccessibilityChildrenVector rowChildren = children();
-    if (!rowChildren.size())
-        return 0;
-
-    // check the first element in the row to see if it is a TH element
-    AXObject* cell = rowChildren[0].get();
-    if (!cell->isTableCell())
-        return 0;
-
-    LayoutObject* cellRenderer = toAXTableCell(cell)->renderer();
-    if (!cellRenderer)
-        return 0;
-
-    Node* cellNode = cellRenderer->node();
-    if (!cellNode || !cellNode->hasTagName(thTag))
-        return 0;
-
-    return cell;
+    return headers[0].get();
 }
 
 void AXTableRow::headerObjectsForRow(AccessibilityChildrenVector& headers)
 {
     if (!m_renderer || !m_renderer->isTableRow())
         return;
 
     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