Add Autofill preview support for <select> input fields

Source/core/html/HTMLSelectElement.cpp

 /*
  * 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) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2009, 2010, 2011 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
@@ skipping 250 matching lines @@
                 setSelectedIndex(optionIndex);
                 return;
             }
             optionIndex++;
         }
     }
 
     setSelectedIndex(-1);
 }
 
+String HTMLSelectElement::suggestedValue() const
+{
+    return m_suggestedValue;
+}
+
+void HTMLSelectElement::setSuggestedValue(const String& value)
+{
+    m_suggestedValue = value;
+
+    setValue(value);
+}
+
+// Original selected option value before autofill preview
+String HTMLSelectElement::originalValue() const
+{
+    return m_originalValue;
+}
+
+void HTMLSelectElement::setOriginalValue(const String& value)
+{
+    m_originalValue = value;
+}
+
 bool HTMLSelectElement::isPresentationAttribute(const QualifiedName& name) const
 {
     if (name == alignAttr) {
         // Don't map 'align' attribute. This matches what Firefox, Opera and IE do.
         // See http://bugs.webkit.org/show_bug.cgi?id=12072
         return false;
     }
 
     return HTMLFormControlElementWithState::isPresentationAttribute(name);
 }
@@ skipping 1288 matching lines @@
     remove(index);
     return true;
 }
 
 bool HTMLSelectElement::isInteractiveContent() const
 {
     return true;
 }
 
 } // namespace