Implement aria properties setsize and posinset.

Source/modules/accessibility/AXNodeObject.cpp

 /*
 * Copyright (C) 2012, Google 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 1247 matching lines @@
         WillBeHeapVector<RefPtrWillBeMember<HTMLFormControlElement>>
             invalidControls;
         bool isInvalid = !element->checkValidity(
             &invalidControls, CheckValidityDispatchNoEvent);
         return isInvalid ? InvalidStateTrue : InvalidStateFalse;
     }
 
     return InvalidStateUndefined;
 }
 
+int AXNodeObject::posInSet() const
+{
+    if (supportsSetSizeAndPosInSet()) {
+        if (hasAttribute(aria_posinsetAttr))
+            return getAttribute(aria_posinsetAttr).toInt();
+        return AXObject::indexInParent();
+    }
+
+    return 0;
+}
+
+int AXNodeObject::setSize() const
+{
+    if (supportsSetSizeAndPosInSet()) {
+        if (hasAttribute(aria_setsizeAttr))
+            return getAttribute(aria_setsizeAttr).toInt();
+
+        const auto& siblings = parentObject()->children();
+        return siblings.size();
+    }
+
+    return 0;
+}
+
 String AXNodeObject::ariaInvalidValue() const
 {
     if (invalidState() == InvalidStateOther)
         return getAttribute(aria_invalidAttr);
 
     return String();
 }
 
 String AXNodeObject::valueDescription() const
 {
@@ skipping 884 matching lines @@
         ariaLabeledByElements(elements);
 
         for (const auto& element : elements) {
             RefPtr<AXObject> axElement = axObjectCache()->getOrCreate(element);
             textOrder.append(AccessibilityText(ariaLabeledBy, AlternativeText, axElement));
         }
     }
 }
 
 } // namespace blink