Add Autofill preview support for <select> input fields

Source/core/testing/Internals.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2013 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.
@@ skipping 992 matching lines @@
         exceptionState.throwDOMException(InvalidNodeTypeError, "The element provided is not a form control element.");
         return String();
     }
 
     String suggestedValue;
     if (element->hasTagName(inputTag))
         suggestedValue = toHTMLInputElement(element)->suggestedValue();
 
     if (element->hasTagName(textareaTag))
         suggestedValue = toHTMLTextAreaElement(element)->suggestedValue();
+
+    if (element->hasTagName(selectTag))
+        suggestedValue = toHTMLSelectElement(element)->suggestedValue();
     return suggestedValue;
 }
 
 void Internals::setSuggestedValue(Element* element, const String& value, ExceptionState& exceptionState)
 {
     if (!element) {
         exceptionState.throwDOMException(InvalidAccessError, ExceptionMessages::argumentNullOrIncorrectType(1, "Element"));
         return;
     }
 
     if (!element->isFormControlElement()) {
         exceptionState.throwDOMException(InvalidNodeTypeError, "The element provided is not a form control element.");
         return;
     }
 
     if (element->hasTagName(inputTag))
         toHTMLInputElement(element)->setSuggestedValue(value);
 
     if (element->hasTagName(textareaTag))
         toHTMLTextAreaElement(element)->setSuggestedValue(value);
+
+    if (element->hasTagName(selectTag))
+        toHTMLSelectElement(element)->setSuggestedValue(value);
 }
 
 void Internals::setEditingValue(Element* element, const String& value, ExceptionState& exceptionState)
 {
     if (!element) {
         exceptionState.throwDOMException(InvalidAccessError, ExceptionMessages::argumentNullOrIncorrectType(1, "Element"));
         return;
     }
 
     if (!element->hasTagName(inputTag)) {
@@ skipping 1338 matching lines @@
     return promise.then(AddOneFunction::create(context));
 }
 
 void Internals::trace(Visitor* visitor)
 {
     visitor->trace(m_runtimeFlags);
     visitor->trace(m_profilers);
 }
 
 }