Have HTMLCollection::item() return an Element as per specification

Source/core/rendering/RenderTheme.cpp

 /**
  * This file is part of the theme implementation for form controls in WebCore.
  *
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Computer, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 914 matching lines @@
     } else {
         tickRect.setWidth(floor(tickSize.height() * zoomFactor));
         tickRect.setHeight(floor(tickSize.width() * zoomFactor));
         tickRect.setX(floor(rect.x() + rect.width() / 2.0 + sliderTickOffsetFromTrackCenter() * zoomFactor));
         tickRegionSideMargin = trackBounds.y() + (thumbSize.width() - tickSize.width() * zoomFactor) / 2.0;
         tickRegionWidth = trackBounds.height() - thumbSize.width();
     }
     RefPtr<HTMLCollection> options = dataList->options();
     GraphicsContextStateSaver stateSaver(*paintInfo.context);
     paintInfo.context->setFillColor(o->resolveColor(CSSPropertyColor));
-    for (unsigned i = 0; Node* node = options->item(i); i++) {
-        ASSERT(node->hasTagName(optionTag));
-        HTMLOptionElement* optionElement = toHTMLOptionElement(node);
+    for (unsigned i = 0; Element* element = options->item(i); i++) {
+        ASSERT(element->hasTagName(optionTag));
+        HTMLOptionElement* optionElement = toHTMLOptionElement(element);
         String value = optionElement->value();
         if (!input->isValidValue(value))
             continue;
         double parsedValue = parseToDoubleForNumberType(input->sanitizeValue(value));
         double tickFraction = (parsedValue - min) / (max - min);
         double tickRatio = isHorizontal && o->style()->isLeftToRightDirection() ? tickFraction : 1.0 - tickFraction;
         double tickPosition = round(tickRegionSideMargin + tickRegionWidth * tickRatio);
         if (isHorizontal)
             tickRect.setX(tickPosition);
         else
@@ skipping 324 matching lines @@
 
     // padding - not honored by WinIE, needs to be removed.
     style->resetPadding();
 
     // border - honored by WinIE, but looks terrible (just paints in the control box and turns off the Windows XP theme)
     // for now, we will not honor it.
     style->resetBorder();
 }
 
 } // namespace WebCore