Provides an API to cope with table headers in Accessibility

Source/web/WebAXObject.cpp

Index: Source/web/WebAXObject.cpp
diff --git a/Source/web/WebAXObject.cpp b/Source/web/WebAXObject.cpp
index 8f1905fea98dd77437579d0ab1cbd7a9b59e3a0b..3013ea133947bf54851d87ef29a229066e6cb33a 100644
--- a/Source/web/WebAXObject.cpp
+++ b/Source/web/WebAXObject.cpp
@@ -1169,6 +1169,29 @@ unsigned WebAXObject::cellRowSpan() const
     return rowRange.second;
 }
 
+void WebAXObject::tableHeaders(WebVector<WebAXObject>& headerElements, bool rowHeaders) const
+{
+    if (isDetached())
+        return;
+
+    if (!m_private->isAXTable())
+        return;
+
+    AXObject::AccessibilityChildrenVector headers;
+    if (rowHeaders)
+        toAXTable(m_private.get())->rowHeaders(headers);
+    else
+        toAXTable(m_private.get())->columnHeaders(headers);
+
+    size_t headerCount = headers.size();
+    WebVector<WebAXObject> result(headerCount);
+
+    for (size_t i = 0; i < headerCount; i++)
+        result[i] = WebAXObject(headers[i]);
+
+    headerElements.swap(result);
+}
+
 void WebAXObject::loadInlineTextBoxes() const
 {
     if (isDetached())