Select elements should clear type-ahead session on blur.

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 135 matching lines @@
     void popupDidCancel();
     // Provisional selection is a selection made using arrow keys or type ahead.
     void provisionalSelectionChanged(unsigned);
     void popupDidHide();
     bool popupIsVisible() const { return m_popupIsVisible; }
     int optionIndexToBeShown() const;
     void showPopup();
     void hidePopup();
     PopupMenu* popup() const { return m_popup.get(); }
 
+    void resetTypeAheadSessionForTesting();
+
     DECLARE_VIRTUAL_TRACE();
 
 protected:
     HTMLSelectElement(Document&, HTMLFormElement*);
 
 private:
     void willRecalcStyle(StyleRecalcChange) override;
 
     const AtomicString& formControlType() const override;
 
@@ skipping 97 matching lines @@
     bool m_isAutofilledByPreview;
 
     RefPtrWillBeMember<PopupMenu> m_popup;
     int m_indexToSelectOnCancel;
     bool m_popupIsVisible;
 };
 
 } // namespace blink
 
 #endif // HTMLSelectElement_h