Fixing a crash in InsertListCommand.

Source/core/editing/InsertListCommand.cpp

 /*
  * Copyright (C) 2006, 2010 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 102 matching lines @@
     VisiblePosition visibleEnd = endingSelection().visibleEnd();
     VisiblePosition visibleStart = endingSelection().visibleStart();
     // When a selection ends at the start of a paragraph, we rarely paint
     // the selection gap before that paragraph, because there often is no gap.
     // In a case like this, it's not obvious to the user that the selection
     // ends "inside" that paragraph, so it would be confusing if InsertUn{Ordered}List
     // operated on that paragraph.
     // FIXME: We paint the gap before some paragraphs that are indented with left
     // margin/padding, but not others.  We should make the gap painting more consistent and
     // then use a left margin/padding rule here.
-    if (visibleEnd != visibleStart && isStartOfParagraph(visibleEnd, CanSkipOverEditingBoundary))
+    if (visibleEnd != visibleStart && isStartOfParagraph(visibleEnd, CanSkipOverEditingBoundary)) {
         setEndingSelection(VisibleSelection(visibleStart, visibleEnd.previous(CannotCrossEditingBoundary), endingSelection().isDirectional()));
+        if (!endingSelection().rootEditableElement())
+            return;
+    }
 
     const QualifiedName& listTag = (m_type == OrderedList) ? olTag : ulTag;
     if (endingSelection().isRange()) {
         VisibleSelection selection = selectionForParagraphIteration(endingSelection());
         ASSERT(selection.isRange());
         VisiblePosition startOfSelection = selection.visibleStart();
         VisiblePosition endOfSelection = selection.visibleEnd();
         VisiblePosition startOfLastParagraph = startOfParagraph(endOfSelection, CanSkipOverEditingBoundary);
 
         if (startOfParagraph(startOfSelection, CanSkipOverEditingBoundary) != startOfLastParagraph) {
@@ skipping 256 matching lines @@
     if (listElement)
         return mergeWithNeighboringLists(listElement);
 
     if (canMergeLists(previousList, nextList))
         mergeIdenticalElements(previousList, nextList);
 
     return listElement;
 }
 
 }