SELECT element: Introduce light-weight OPTION iterater.

third_party/WebKit/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 869 matching lines @@
     if (multiple())
         return;
     HTMLOptionElement* firstEnabledOption = nullptr;
     int firstEnabledOptionIndex = -1;
     HTMLOptionElement* lastSelectedOption = nullptr;
     bool didChange = false;
     int optionIndex = 0;
     // We can't use HTMLSelectElement::options here because this function is
     // called in Node::insertedInto and Node::removedFrom before invalidating
     // node collections.
-    for (auto& item : listItems()) {
-        if (!isHTMLOptionElement(item))
-            continue;
-        HTMLOptionElement* option = toHTMLOptionElement(item);
+    for (const auto& option : optionList()) {
         if (option->selected()) {
             if (lastSelectedOption) {
                 lastSelectedOption->setSelectedState(false);
                 didChange = true;
             }
             lastSelectedOption = option;
         }
         if (!firstEnabledOption && !option->isDisabledFormControl()) {
             firstEnabledOption = option;
             firstEnabledOptionIndex = optionIndex;
@@ skipping 1226 matching lines @@
 }
 
 void HTMLSelectElement::didMutateSubtree()
 {
     DCHECK(popupIsVisible());
     DCHECK(m_popup);
     m_popup->updateFromElement(PopupMenu::ByDOMChange);
 }
 
 } // namespace blink