Make it obvious an HTMLOptionsCollection can only contain HTMLOptionElements

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 207 matching lines @@
 
     if (!element || !(isHTMLOptionElement(element) || isHTMLOptGroupElement(element) || isHTMLHRElement(element)))
         return;
 
     insertBefore(element, before, exceptionState);
     setNeedsValidityCheck();
 }
 
 void HTMLSelectElement::addBeforeOptionAtIndex(HTMLElement* element, int beforeIndex, ExceptionState& exceptionState)
 {
-    HTMLElement* beforeElement = toHTMLElement(options()->item(beforeIndex));
+    HTMLOptionElement* beforeElement = options()->item(beforeIndex);
     add(element, beforeElement, exceptionState);
 }
 
 void HTMLSelectElement::remove(int optionIndex)
 {
     int listIndex = optionToListIndex(optionIndex);
     if (listIndex < 0)
         return;
 
     listItems()[listIndex]->remove(IGNORE_EXCEPTION);
@@ skipping 206 matching lines @@
 void HTMLSelectElement::setSize(int size)
 {
     setIntegralAttribute(sizeAttr, size);
 }
 
 Element* HTMLSelectElement::namedItem(const AtomicString& name)
 {
     return options()->namedItem(name);
 }
 
-Element* HTMLSelectElement::item(unsigned index)
+HTMLOptionElement* HTMLSelectElement::item(unsigned index)
 {
     return options()->item(index);
 }
 
 void HTMLSelectElement::setOption(unsigned index, HTMLOptionElement* option, ExceptionState& exceptionState)
 {
     if (index > maxSelectItems - 1)
         index = maxSelectItems - 1;
     int diff = index - length();
-    RefPtrWillBeRawPtr<HTMLElement> before = nullptr;
+    RefPtrWillBeRawPtr<HTMLOptionElement> before = nullptr;
     // Out of array bounds? First insert empty dummies.
     if (diff > 0) {
         setLength(index, exceptionState);
         // Replace an existing entry?
     } else if (diff < 0) {
-        before = toHTMLElement(options()->item(index+1));
+        before = options()->item(index + 1);
         remove(index);
     }
     // Finally add the new element.
     if (!exceptionState.hadException()) {
         add(option, before.get(), exceptionState);
         if (diff >= 0 && option->selected())
             optionSelectionStateChanged(option, true);
     }
 }
 
@@ skipping 1258 matching lines @@
     int focusedIndex = activeSelectionEndListIndex();
     if (focusedIndex < 0)
         focusedIndex = firstSelectableListIndex();
     if (focusedIndex < 0)
         return nullptr;
     HTMLElement* focused = listItems()[focusedIndex];
     return isHTMLOptionElement(focused) ? toHTMLOptionElement(focused) : nullptr;
 }
 
 } // namespace