Make replacing selection in heading/paragraph with heading/paragraph to work

Source/core/editing/ReplaceSelectionCommand.cpp

 /*
  * Copyright (C) 2005, 2006, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2009, 2010, 2011 Google 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 620 matching lines @@
                 moveNodeOutOfAncestor(node, headerElement);
         }
     }
 }
 
 void ReplaceSelectionCommand::moveNodeOutOfAncestor(PassRefPtr<Node> prpNode, PassRefPtr<Node> prpAncestor)
 {
     RefPtr<Node> node = prpNode;
     RefPtr<Node> ancestor = prpAncestor;
 
+    if (!ancestor->parentNode()->rendererIsEditable())
+        return;
+
     VisiblePosition positionAtEndOfNode = lastPositionInOrAfterNode(node.get());
     VisiblePosition lastPositionInParagraph = lastPositionInNode(ancestor.get());
     if (positionAtEndOfNode == lastPositionInParagraph) {
         removeNode(node);
         if (ancestor->nextSibling())
             insertNodeBefore(node, ancestor->nextSibling());
         else
             appendNode(node, ancestor->parentNode());
     } else {
         RefPtr<Node> nodeToSplitTo = splitTreeToNode(node.get(), ancestor.get(), true);
@@ skipping 833 matching lines @@
         removeNodeAndPruneAncestors(nodeAfterInsertionPos.get());
 
     VisibleSelection selectionAfterReplace(m_selectReplacement ? start : end, end);
 
     setEndingSelection(selectionAfterReplace);
 
     return true;
 }
 
 } // namespace WebCore