Implement aria properties setsize and posinset.

Source/modules/accessibility/AXObject.cpp

 /*
  * Copyright (C) 2008, 2009, 2011 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 700 matching lines @@
 
 bool AXObject::supportsRangeValue() const
 {
     return isProgressIndicator()
         || isMeter()
         || isSlider()
         || isScrollbar()
         || isSpinButton();
 }
 
+bool AXObject::supportsSetSizeAndPosInSet() const
+{
+    AXObject* parent = parentObject();
+    if (!parent)
+        return false;
+
+    int role = roleValue();
+    int parentRole = parent->roleValue();
+
+    if ((role == ListBoxOptionRole && parentRole == ListBoxRole)
+        || (role == ListItemRole && parentRole == ListRole)
+        || (role == MenuItemRole && parentRole == MenuRole)
+        || (role == RadioButtonRole && parentRole == RadioGroupRole)
+        || (role == TabRole && parentRole == TabListRole)
+        || (role == TreeItemRole && parentRole == TreeRole))
+        return true;
+
+    return false;
+}
+
+int AXObject::indexInParent() const
+{
+    if (!parentObject())
+        return 0;
+
+    const auto& siblings = parentObject()->children();
+    int childCount = siblings.size();
+
+    for (int index = 0; index < childCount; ++index) {
+        if (siblings[index].get() == this) {
+            return index;
+        }
+    }
+    return 0;
+}
+
 void AXObject::ariaTreeRows(AccessibilityChildrenVector& result)
 {
     for (const auto& child : children()) {
         // Add tree items as the rows.
         if (child->roleValue() == TreeItemRole)
             result.append(child);
 
         // Now see if this item also has rows hiding inside of it.
         child->ariaTreeRows(result);
     }
@@ skipping 568 matching lines @@
 }
 
 const AtomicString& AXObject::internalRoleName(AccessibilityRole role)
 {
     static const Vector<AtomicString>* internalRoleNameVector = createInternalRoleNameVector();
 
     return internalRoleNameVector->at(role);
 }
 
 } // namespace blink