Bug 1796733 part 5: Add an overload of nsAccUtils::NormalizeARIAToken which takes an Element. r=avandolder

The next patch in this stack adds a method to retrieve aria-selected.
The easiest way to do this is using NormalizeARIAToken.
This overload takes an Element and checks both the Element and ElementInternals.

Differential Revision: https://phabricator.services.mozilla.com/D161241

accessible/base/nsAccUtils.cpp

@@ -176,6 +176,19 @@ nsStaticAtom* nsAccUtils::NormalizeARIAToken(const AttrArray* aAttrs,
   return nullptr;
 }
 
+nsStaticAtom* nsAccUtils::NormalizeARIAToken(dom::Element* aElement,
+                                             nsAtom* aAttr) {
+  if (auto* htmlElement = nsGenericHTMLElement::FromNode(aElement);
+      htmlElement && !aElement->HasAttr(aAttr)) {
+    const auto* defaults = GetARIADefaults(htmlElement);
+    if (!defaults) {
+      return nsGkAtoms::_empty;
+    }
+    return NormalizeARIAToken(defaults, aAttr);
+  }
+  return NormalizeARIAToken(&aElement->GetAttrs(), aAttr);
+}
+
 Accessible* nsAccUtils::GetSelectableContainer(const Accessible* aAccessible,
                                                uint64_t aState) {
   if (!aAccessible) return nullptr;

accessible/base/nsAccUtils.h

@@ -68,6 +68,8 @@ class nsAccUtils {
    */
   static nsStaticAtom* NormalizeARIAToken(const AttrArray* aAttrs,
                                           nsAtom* aAttr);
+  static nsStaticAtom* NormalizeARIAToken(mozilla::dom::Element* aElement,
+                                          nsAtom* aAttr);
 
   /**
    * Return document accessible for the given DOM node.