Merge to M51: Accessible name calc should allow aria-labelledby to reference aria-hidden

third_party/WebKit/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 1602 matching lines @@
     HeapVector<Member<AXObject>> ownedChildren;
     computeAriaOwnsChildren(ownedChildren);
     for (AXObject* obj = rawFirstChild(); obj; obj = obj->rawNextSibling()) {
         if (!axObjectCache().isAriaOwned(obj))
             children.append(obj);
     }
     for (const auto& ownedChild : ownedChildren)
         children.append(ownedChild);
 
     for (AXObject* child : children) {
-        // Skip hidden children
-        if (child->isInertOrAriaHidden())
+        // Don't recurse into children that are explicitly marked as aria-hidden.
+        // Note that we don't call isInertOrAriaHidden because that would return true
+        // if any ancestor is hidden, but we need to be able to compute the accessible
+        // name of object inside hidden subtrees (for example, if aria-labelledby points
+        // to an object that's hidden).
+        if (equalIgnoringCase(child->getAttribute(aria_hiddenAttr), "true"))
             continue;
 
         // If we're going between two layoutObjects that are in separate LayoutBoxes, add
         // whitespace if it wasn't there already. Intuitively if you have
         // <span>Hello</span><span>World</span>, those are part of the same LayoutBox
         // so we should return "HelloWorld", but given <div>Hello</div><div>World</div> the
         // strings are in separate boxes so we should return "Hello World".
         if (previous && accumulatedText.length() && !isHTMLSpace(accumulatedText[accumulatedText.length() - 1])) {
             if (!isInSameNonInlineBlockFlow(child->getLayoutObject(), previous->getLayoutObject()))
                 accumulatedText.append(' ');
@@ skipping 1124 matching lines @@
     return placeholder;
 }
 
 DEFINE_TRACE(AXNodeObject)
 {
     visitor->trace(m_node);
     AXObject::trace(visitor);
 }
 
 } // namespace blink