Clean up forward declarations in Source/core/editing

Source/core/editing/EditCommand.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 16 matching lines @@
 #define EditCommand_h
 
 #include "core/editing/EditAction.h"
 #include "core/editing/VisibleSelection.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
 class CompositeEditCommand;
 class Document;
-class Element;
 
 class EditCommand : public RefCountedWillBeGarbageCollectedFinalized<EditCommand> {
 public:
     virtual ~EditCommand();
 
     void setParent(CompositeEditCommand*);
 
     virtual EditAction editingAction() const;
 
     const VisibleSelection& startingSelection() const { return m_startingSelection; }
@@ skipping 40 matching lines @@
 
 private:
     virtual bool isSimpleEditCommand() const OVERRIDE FINAL { return true; }
 };
 
 DEFINE_TYPE_CASTS(SimpleEditCommand, EditCommand, command, command->isSimpleEditCommand(), command.isSimpleEditCommand());
 
 } // namespace blink
 
 #endif // EditCommand_h