Fix issue on <select> style change when popup is visible

Source/web/PopupMenuImpl.h

 // Copyright (c) 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef PopupMenuImpl_h
 #define PopupMenuImpl_h
 
 #include "core/html/forms/PopupMenuClient.h"
 #include "core/page/PagePopupClient.h"
 #include "platform/PopupMenu.h"
@@ skipping 35 matching lines @@
     void setValueAndClosePopup(int, const String&) override;
     void setValue(const String&) override;
     void closePopup() override;
     Element& ownerElement() override;
     Locale& locale() override;
     void didClosePopup() override;
 
     ChromeClientImpl* m_chromeClient;
     PopupMenuClient* m_client;
     PagePopup* m_popup;
-    // If >= 0, this is the index we should accept when the popup closes.
-    // This is used for keyboard navigation, where we want the
-    // text to change immediately but set the value on close.
-    int m_indexToSetOnClose;
 };
 
 }
 
 #endif // PopupMenuImpl_h