Ignores ARIA relations (e.g. aria-labelledby) that point to an invisible target.

third_party/WebKit/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 19 matching lines @@
 
 #include "core/editing/EditingUtilities.h"
 #include "core/editing/VisibleUnits.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
 #include "core/html/HTMLDialogElement.h"
 #include "core/html/HTMLFrameOwnerElement.h"
 #include "core/html/parser/HTMLParserIdioms.h"
 #include "core/layout/LayoutTheme.h"
+#include "core/style/ComputedStyleConstants.h"
 #include "modules/accessibility/AXObjectCacheImpl.h"
 #include "platform/UserGestureIndicator.h"
 #include "platform/text/PlatformLocale.h"
 #include "wtf/HashSet.h"
 #include "wtf/StdLibExtras.h"
 #include "wtf/text/WTFString.h"
 
 using blink::WebLocalizedString;
 
 namespace blink {
@@ skipping 843 matching lines @@
 
 void AXObject::elementsFromAttribute(HeapVector<Member<Element>>& elements, const QualifiedName& attribute) const
 {
     Vector<String> ids;
     tokenVectorFromAttribute(ids, attribute);
     if (ids.isEmpty())
         return;
 
     TreeScope& scope = getNode()->treeScope();
     for (const auto& id : ids) {
-        if (Element* idElement = scope.getElementById(AtomicString(id)))
+        if (Element* idElement = scope.getElementById(AtomicString(id))) {

[aboxhall, 2016/07/08 17:12:35]

Something weird happened here, does this file need to be in this CL?

             elements.append(idElement);
+        }
     }
 }
 
 void AXObject::ariaLabelledbyElementVector(HeapVector<Member<Element>>& elements) const
 {
     // Try both spellings, but prefer aria-labelledby, which is the official spec.
     elementsFromAttribute(elements, aria_labelledbyAttr);
     if (!elements.size())
         elementsFromAttribute(elements, aria_labeledbyAttr);
 }
@@ skipping 833 matching lines @@
 
 DEFINE_TRACE(AXObject)
 {
     visitor->trace(m_children);
     visitor->trace(m_parent);
     visitor->trace(m_cachedLiveRegionRoot);
     visitor->trace(m_axObjectCache);
 }
 
 } // namespace blink