Use tighter typing in editing/

Source/core/editing/WrapContentsInDummySpanCommand.h

 /*
  * Copyright (C) 2005, 2006, 2008 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 12 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef WrapContentsInDummySpanCommand_h
 #define WrapContentsInDummySpanCommand_h
 
 #include "core/editing/EditCommand.h"
 
 namespace blink {
 
-class HTMLElement;
+class HTMLSpanElement;
 
 class WrapContentsInDummySpanCommand FINAL : public SimpleEditCommand {
 public:
     static PassRefPtrWillBeRawPtr<WrapContentsInDummySpanCommand> create(PassRefPtrWillBeRawPtr<Element> element)
     {
         return adoptRefWillBeNoop(new WrapContentsInDummySpanCommand(element));
     }
 
     virtual void trace(Visitor*) OVERRIDE;
 
 private:
     explicit WrapContentsInDummySpanCommand(PassRefPtrWillBeRawPtr<Element>);
 
     virtual void doApply() OVERRIDE;
     virtual void doUnapply() OVERRIDE;
     virtual void doReapply() OVERRIDE;
     void executeApply();
 
     RefPtrWillBeMember<Element> m_element;
-    RefPtrWillBeMember<HTMLElement> m_dummySpan;
+    RefPtrWillBeMember<HTMLSpanElement> m_dummySpan;
 };
 
 } // namespace blink
 
 #endif // WrapContentsInDummySpanCommand_h