Use union types for HTMLSelectElement.add()'s arguments

Source/core/html/HTMLSelectElement.h

 /*
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 19 matching lines @@
 #include "core/html/HTMLFormControlElementWithState.h"
 #include "core/html/HTMLOptionsCollection.h"
 #include "core/html/forms/TypeAhead.h"
 #include "wtf/Vector.h"
 
 namespace blink {
 
 class AutoscrollController;
 class ExceptionState;
 class HTMLOptionElement;
+class HTMLOptionElementOrHTMLOptGroupElement;
+class HTMLElementOrLong;
 
 class HTMLSelectElement final : public HTMLFormControlElementWithState, public TypeAheadDataSource {
     DEFINE_WRAPPERTYPEINFO();
 public:
     static PassRefPtrWillBeRawPtr<HTMLSelectElement> create(Document&);
     static PassRefPtrWillBeRawPtr<HTMLSelectElement> create(Document&, HTMLFormElement*);
 
     int selectedIndex() const;
     void setSelectedIndex(int);
     int suggestedIndex() const;
     void setSuggestedIndex(int);
 
     void optionSelectedByUser(int index, bool dispatchChangeEvent, bool allowMultipleSelection = false);
 
     // For ValidityState
     virtual String validationMessage() const override;
     virtual bool valueMissing() const override;
 
     virtual void resetImpl() override;
 
     unsigned length() const;
 
     int size() const { return m_size; }
     bool multiple() const { return m_multiple; }
 
     bool usesMenuList() const;
 
-    void add(HTMLElement*, HTMLElement* beforeElement, ExceptionState&);
-    void addBeforeOptionAtIndex(HTMLElement*, int beforeIndex, ExceptionState&);
+    void add(const HTMLOptionElementOrHTMLOptGroupElement&, const HTMLElementOrLong&, ExceptionState&);
 
     using Node::remove;
     void remove(int index);
 
     String value() const;
     void setValue(const String&, bool sendEvents = false);
     String suggestedValue() const;
     void setSuggestedValue(const String&);
 
     PassRefPtrWillBeRawPtr<HTMLOptionsCollection> options();
@@ skipping 147 matching lines @@
     bool m_multiple;
     bool m_activeSelectionState;
     mutable bool m_shouldRecalcListItems;
     int m_suggestedIndex;
     bool m_isAutofilledByPreview;
 };
 
 } // namespace blink
 
 #endif // HTMLSelectElement_h