Avoid adding placeholder when deleting last text in root

Source/core/editing/DeleteSelectionCommand.cpp

 /*
  * Copyright (C) 2005 Apple Computer, 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 754 matching lines @@
     if (!m_hasSelectionToDelete)
         m_selectionToDelete = endingSelection();
 
     if (!m_selectionToDelete.isNonOrphanedRange())
         return;
 
     // save this to later make the selection with
     EAffinity affinity = m_selectionToDelete.affinity();
     
     Position downstreamEnd = m_selectionToDelete.end().downstream();
-    m_needPlaceholder = isStartOfParagraph(m_selectionToDelete.visibleStart(), CanCrossEditingBoundary)
-            && isEndOfParagraph(m_selectionToDelete.visibleEnd(), CanCrossEditingBoundary)
-            && !lineBreakExistsAtVisiblePosition(m_selectionToDelete.visibleEnd());
+    bool rootWillStayOpenWithoutPlaceholder = downstreamEnd.containerNode() == downstreamEnd.containerNode()->rootEditableElement()
+        || (downstreamEnd.containerNode()->isTextNode() && downstreamEnd.containerNode()->parentNode() == downstreamEnd.containerNode()->rootEditableElement());
+    m_needPlaceholder = !rootWillStayOpenWithoutPlaceholder
+        && isStartOfParagraph(m_selectionToDelete.visibleStart(), CanCrossEditingBoundary)
+        && isEndOfParagraph(m_selectionToDelete.visibleEnd(), CanCrossEditingBoundary)
+        && !lineBreakExistsAtVisiblePosition(m_selectionToDelete.visibleEnd());
     if (m_needPlaceholder) {
         // Don't need a placeholder when deleting a selection that starts just before a table
         // and ends inside it (we do need placeholders to hold open empty cells, but that's
         // handled elsewhere).
         if (Node* table = isLastPositionBeforeTable(m_selectionToDelete.visibleStart()))
             if (m_selectionToDelete.end().deprecatedNode()->isDescendantOf(table))
                 m_needPlaceholder = false;
     }
         
     
@@ skipping 49 matching lines @@
 
 // Normally deletion doesn't preserve the typing style that was present before it.  For example,
 // type a character, Bold, then delete the character and start typing.  The Bold typing style shouldn't
 // stick around.  Deletion should preserve a typing style that *it* sets, however.
 bool DeleteSelectionCommand::preservesTypingStyle() const
 {
     return m_typingStyle;
 }
 
 } // namespace WebCore