Fix crash when cached parent of AXLayoutObject is stale.

third_party/WebKit/Source/modules/accessibility/AXLayoutObject.cpp

 /*
 * Copyright (C) 2008 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 1621 matching lines @@
 
     m_haveChildren = true;
 
     if (!canHaveChildren())
         return;
 
     HeapVector<Member<AXObject>> ownedChildren;
     computeAriaOwnsChildren(ownedChildren);
 
     for (AXObject* obj = rawFirstChild(); obj; obj = obj->rawNextSibling()) {
-        if (!axObjectCache().isAriaOwned(obj))
+        if (!axObjectCache().isAriaOwned(obj)) {
+            obj->setParent(this);
             addChild(obj);
+        }
     }
 
     addHiddenChildren();
     addAttachmentChildren();
     addPopupChildren();
     addImageMapChildren();
     addTextFieldChildren();
     addCanvasChildren();
     addRemoteSVGChildren();
     addInlineTextBoxChildren(false);
@@ skipping 873 matching lines @@
         if (label && label->layoutObject()) {
             LayoutRect labelRect = axObjectCache().getOrCreate(label)->elementRect();
             result.unite(labelRect);
         }
     }
 
     return result;
 }
 
 } // namespace blink