HTML select element should return ComboBoxRole when multiple attr is not present.

Source/modules/accessibility/AXNodeObject.cpp

 /*
 * Copyright (C) 2012, Google 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
@@ skipping 223 matching lines @@
         if (type == InputTypeNames::range)
             return SliderRole;
         if (type == InputTypeNames::color)
             return ColorWellRole;
         if (type == InputTypeNames::time)
             return TimeRole;
         return TextFieldRole;
     }
     if (isHTMLSelectElement(*node())) {
         HTMLSelectElement& selectElement = toHTMLSelectElement(*node());
-        return selectElement.multiple() ? ListBoxRole : PopUpButtonRole;
+        return selectElement.multiple() ? ListBoxRole : ComboBoxRole;
     }
     if (isHTMLTextAreaElement(*node()))
         return TextAreaRole;
     if (headingLevel())
         return HeadingRole;
     if (isHTMLDivElement(*node()))
         return DivRole;
     if (isHTMLMeterElement(*node()))
         return MeterRole;
     if (isHTMLOutputElement(*node()))
@@ skipping 1570 matching lines @@
     float range = maxValueForRange() - minValueForRange();
     float value = valueForRange();
 
     value += range * (percentChange / 100);
     setValue(String::number(value));
 
     axObjectCache()->postNotification(node(), AXObjectCacheImpl::AXValueChanged, true);
 }
 
 } // namespace blink