Merge 94793 - Crashes in WebCore::ReplaceSelectionCommand::doApply

Source/WebCore/editing/ReplaceSelectionCommand.cpp

 /*
  * Copyright (C) 2005, 2006, 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 976 matching lines @@
     
     VisiblePosition startOfInsertedContent, endOfInsertedContent;
     
     RefPtr<Node> refNode = fragment.firstChild();
     RefPtr<Node> node = refNode->nextSibling();
     
     fragment.removeNode(refNode);
 
     Node* blockStart = enclosingBlock(insertionPos.deprecatedNode());
     if ((isListElement(refNode.get()) || (isLegacyAppleStyleSpan(refNode.get()) && isListElement(refNode->firstChild())))
-        && blockStart->renderer()->isListItem())
+        && blockStart && blockStart->renderer()->isListItem())
         refNode = insertAsListItems(refNode, blockStart, insertionPos);
     else
         insertNodeAtAndUpdateNodesInserted(refNode, insertionPos);
 
     // Mutation events (bug 22634) may have already removed the inserted content
     if (!refNode->inDocument())
         return;
 
     bool plainTextFragment = isPlainTextMarkup(refNode.get());
 
@@ skipping 319 matching lines @@
         return false;
 
     VisibleSelection selectionAfterReplace(m_selectReplacement ? start : end, end);
 
     setEndingSelection(selectionAfterReplace);
 
     return true;
 }
 
 } // namespace WebCore