Use tighter typing in editing/

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 80 matching lines @@
     , m_selectionToDelete(selection)
     , m_startBlock(nullptr)
     , m_endBlock(nullptr)
     , m_typingStyle(nullptr)
     , m_deleteIntoBlockquoteStyle(nullptr)
 {
 }
 
 void DeleteSelectionCommand::initializeStartEnd(Position& start, Position& end)
 {
-    Node* startSpecialContainer = 0;
-    Node* endSpecialContainer = 0;
+    HTMLElement* startSpecialContainer = 0;
+    HTMLElement* endSpecialContainer = 0;
 
     start = m_selectionToDelete.start();
     end = m_selectionToDelete.end();
 
     // For HRs, we'll get a position at (HR,1) when hitting delete from the beginning of the previous line, or (HR,0) when forward deleting,
     // but in these cases, we want to delete it, so manually expand the selection
     if (isHTMLHRElement(*start.deprecatedNode()))
         start = positionBeforeNode(start.deprecatedNode());
     else if (isHTMLHRElement(*end.deprecatedNode()))
         end = positionAfterNode(end.deprecatedNode());
@@ skipping 771 matching lines @@
     visitor->trace(m_deleteIntoBlockquoteStyle);
     visitor->trace(m_startRoot);
     visitor->trace(m_endRoot);
     visitor->trace(m_startTableRow);
     visitor->trace(m_endTableRow);
     visitor->trace(m_temporaryPlaceholder);
     CompositeEditCommand::trace(visitor);
 }
 
 } // namespace blink