Avoid adding placeholder when deleting last text in root

Source/core/editing/DeleteSelectionCommand.cpp

Index: Source/core/editing/DeleteSelectionCommand.cpp
diff --git a/Source/core/editing/DeleteSelectionCommand.cpp b/Source/core/editing/DeleteSelectionCommand.cpp
index 9ba5478843d829c558f1d7882ba0384f3f6fa488..91813a5a2e75a965fd5b5688506efa6b61c6c1b7 100644
--- a/Source/core/editing/DeleteSelectionCommand.cpp
+++ b/Source/core/editing/DeleteSelectionCommand.cpp
@@ -763,9 +763,12 @@ void DeleteSelectionCommand::doApply()
     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