Fixed crash by checking if m_layoutObject->node() is not nullptr before calling isContentRichlyEdit…

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 357 matching lines @@
 static bool isLinkable(const AXObject& object)
 {
     if (!object.layoutObject())
         return false;
 
     // See https://wiki.mozilla.org/Accessibility/AT-Windows-API for the elements
     // Mozilla considers linkable.
     return object.isLink() || object.isImage() || object.layoutObject()->isText();
 }
 
+// Requires layoutObject to be present because it relies on style
+// user-modify. Don't move this logic to AXNodeObject.
+// TODO(nektar): Implement support in AXNodeObject for aria-hidden and canvas.
 bool AXLayoutObject::isRichlyEditable() const
 {
-    ASSERT(node());
-    ASSERT(m_layoutObject);
-
-    // Requires m_layoutObject to be present because it relies on style
-    // user-modify. Don't move this logic to AXNodeObject.
-    // TODO(nektar): Implement support in AXNodeObject for aria-hidden and canvas.
-    if (node()->isContentRichlyEditable())
+    if (node() && node()->isContentRichlyEditable())
         return true;
 
     if (isWebArea()) {
         Document& document = m_layoutObject->document();
         HTMLElement* body = document.body();
         if (body && body->isContentRichlyEditable())
             return true;
 
         return document.isContentRichlyEditable();
     }
@@ skipping 2113 matching lines @@
         if (label && label->layoutObject()) {
             LayoutRect labelRect = axObjectCache()->getOrCreate(label)->elementRect();
             result.unite(labelRect);
         }
     }
 
     return result;
 }
 
 } // namespace blink