Assigned ax role for table headers.

Source/modules/accessibility/AXTableCell.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 73 matching lines @@
 
 bool AXTableCell::isTableCell() const
 {
     AXObject* parent = parentObjectUnignored();
     if (!parent || !parent->isTableRow())
         return false;
 
     return true;
 }
 
+static AccessibilityRole decideRoleFromSibling(Node* siblingNode)
+{
+    if (!siblingNode)
+        return CellRole;
+    if (siblingNode->hasTagName(thTag))
+        return ColumnHeaderRole;
+    if (siblingNode->hasTagName(tdTag))
+        return RowHeaderRole;
+    return CellRole;
+}
+
+AccessibilityRole AXTableCell::scanToDecideHeaderRole()
+{
+    Node* node = m_renderer ? m_renderer->node() : 0;
+    if (!node || !node->hasTagName(thTag))
+        return CellRole;
+
+    // Check scope attribute first.
+    const AtomicString& scope = getAttribute(scopeAttr);
+    if (equalIgnoringCase(scope, "row"))
+        return RowHeaderRole;
+    if (equalIgnoringCase(scope, "col"))
+        return ColumnHeaderRole;
+
+    // Check the previous cell and the next cell
+    RenderTableCell* renderCell = toRenderTableCell(m_renderer);
+    AccessibilityRole headerRole = CellRole;
+
+    // if header is preceded by header cells then it's a column header,
+    // if it is preceded by cells then it's a row header.
+    if (RenderTableCell* cell = renderCell->previousCell()) {
+        Node* siblingNode = cell->node();
+        headerRole = decideRoleFromSibling(siblingNode);
+        if (headerRole != CellRole)
+            return headerRole;
+    }
+    // if header is followed by header cells then it's a column header,
+    // if it is followed by cells then it's a row header.
+    if (RenderTableCell* cell = renderCell->nextCell()) {
+        Node* siblingNode = cell->node();
+        headerRole = decideRoleFromSibling(siblingNode);
+    }
+    return headerRole;
+}
+
 AccessibilityRole AXTableCell::determineAccessibilityRole()
 {
     if (!isTableCell())
         return AXRenderObject::determineAccessibilityRole();
 
-    return CellRole;
+    return scanToDecideHeaderRole();
 }
 
 void AXTableCell::rowIndexRange(pair<unsigned, unsigned>& rowRange)
 {
     if (!m_renderer || !m_renderer->isTableCell())
         return;
 
     RenderTableCell* renderCell = toRenderTableCell(m_renderer);
     rowRange.first = renderCell->rowIndex();
     rowRange.second = renderCell->rowSpan();
@@ skipping 58 matching lines @@
         return 0;
 
     Node* cellElement = headerCell->node();
     if (!cellElement || !cellElement->hasTagName(thTag))
         return 0;
 
     return axObjectCache()->getOrCreate(headerCell);
 }
 
 } // namespace blink