Introduce isHTMLOptGroupElement and toHTMLOptGroupElement

Source/core/rendering/RenderListBox.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  *               2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer. 
@@ skipping 103 matching lines @@
 
     if (m_optionsChanged) {
         const Vector<HTMLElement*>& listItems = selectElement()->listItems();
         int size = numItems();
         
         float width = 0;
         for (int i = 0; i < size; ++i) {
             HTMLElement* element = listItems[i];
             String text;
             Font itemFont = style()->font();
-            if (element->hasTagName(optionTag))
+            if (element->hasTagName(optionTag)) {
                 text = toHTMLOptionElement(element)->textIndentedToRespectGroupLabel();
-            else if (element->hasTagName(optgroupTag)) {
-                text = static_cast<const HTMLOptGroupElement*>(element)->groupLabelText();
+            } else if (isHTMLOptGroupElement(element)) {
+                text = toHTMLOptGroupElement(element)->groupLabelText();
                 FontDescription d = itemFont.fontDescription();
                 d.setWeight(d.bolderWeight());
                 itemFont = Font(d, itemFont.letterSpacing(), itemFont.wordSpacing());
                 itemFont.update(document()->styleResolver()->fontSelector());
             }
 
             if (!text.isEmpty()) {
                 applyTextTransform(style(), text, ' ');
                 // FIXME: Why is this always LTR? Can't text direction affect the width?
                 TextRun textRun = constructTextRun(this, itemFont, text, style(), TextRun::AllowTrailingExpansion);
@@ skipping 258 matching lines @@
     if (!itemStyle)
         itemStyle = style();
 
     if (itemStyle->visibility() == HIDDEN)
         return;
 
     String itemText;
     bool isOptionElement = element->hasTagName(optionTag);
     if (isOptionElement)
         itemText = toHTMLOptionElement(element)->textIndentedToRespectGroupLabel();
-    else if (element->hasTagName(optgroupTag))
-        itemText = static_cast<const HTMLOptGroupElement*>(element)->groupLabelText();
+    else if (isHTMLOptGroupElement(element))
+        itemText = toHTMLOptGroupElement(element)->groupLabelText();
     applyTextTransform(style(), itemText, ' ');
 
     Color textColor = element->renderStyle() ? element->renderStyle()->visitedDependentColor(CSSPropertyColor) : style()->visitedDependentColor(CSSPropertyColor);
     if (isOptionElement && toHTMLOptionElement(element)->selected()) {
         if (frame()->selection()->isFocusedAndActive() && document()->focusedNode() == node())
             textColor = theme()->activeListBoxSelectionForegroundColor();
         // Honor the foreground color for disabled items
         else if (!element->isDisabledFormControl() && !select->isDisabledFormControl())
             textColor = theme()->inactiveListBoxSelectionForegroundColor();
     }
 
     paintInfo.context->setFillColor(textColor);
 
     TextRun textRun(itemText, 0, 0, TextRun::AllowTrailingExpansion, itemStyle->direction(), isOverride(itemStyle->unicodeBidi()), true, TextRun::NoRounding);
     Font itemFont = style()->font();
     LayoutRect r = itemBoundingBoxRect(paintOffset, listIndex);
     r.move(itemOffsetForAlignment(textRun, itemStyle, itemFont, r));
 
-    if (element->hasTagName(optgroupTag)) {
+    if (isHTMLOptGroupElement(element)) {
         FontDescription d = itemFont.fontDescription();
         d.setWeight(d.bolderWeight());
         itemFont = Font(d, itemFont.letterSpacing(), itemFont.wordSpacing());
         itemFont.update(document()->styleResolver()->fontSelector());
     }
 
     // Draw the item text
     TextRunPaintInfo textRunPaintInfo(textRun);
     textRunPaintInfo.bounds = r;
     paintInfo.context->drawBidiText(itemFont, textRunPaintInfo, roundedIntPoint(r.location()));
@@ skipping 451 matching lines @@
 
     if (m_vBar)
         m_vBar->styleChanged();
 
     // Force an update since we know the scrollbars have changed things.
     if (document()->hasAnnotatedRegions())
         document()->setAnnotatedRegionsDirty(true);
 }
 
 } // namespace WebCore