Add Autofill preview support for <select> input fields

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 50 matching lines @@
     bool usesMenuList() const;
 
     void add(HTMLElement*, HTMLElement* beforeElement, ExceptionState&);
 
     using Node::remove;
     void remove(int index);
     void remove(HTMLOptionElement*);
 
     String value() const;
     void setValue(const String&);
+    String suggestedValue() const;
+    void setSuggestedValue(const String&);
+    String originalValue() const;
+    void setOriginalValue(const String&);
 
     PassRefPtr<HTMLOptionsCollection> options();
     PassRefPtr<HTMLCollection> selectedOptions();
 
     void optionElementChildrenChanged();
 
     void setRecalcListItems();
     void invalidateSelectedItems();
     void updateListItemSelectedStates();
 
@@ skipping 120 matching lines @@
     TypeAhead m_typeAhead;
     int m_size;
     int m_lastOnChangeIndex;
     int m_activeSelectionAnchorIndex;
     int m_activeSelectionEndIndex;
     bool m_isProcessingUserDrivenChange;
     bool m_multiple;
     bool m_activeSelectionState;
     mutable bool m_shouldRecalcListItems;
     bool m_isParsingInProgress;
+    String m_suggestedValue;
+    String m_originalValue;
 };
 
 DEFINE_NODE_TYPE_CASTS(HTMLSelectElement, hasTagName(HTMLNames::selectTag));
 
 } // namespace
 
 #endif