Use new is*Element() helper functions more in rendering code

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 693 matching lines @@
 
     Page* page = node->document().page();
     if (!page)
         return false;
 
     return page->focusController().isActive();
 }
 
 bool RenderTheme::isChecked(const RenderObject* o) const
 {
-    if (!o->node() || !o->node()->hasTagName(inputTag))
+    if (!isHTMLInputElement(o->node()))
         return false;
     return toHTMLInputElement(o->node())->shouldAppearChecked();
 }
 
 bool RenderTheme::isIndeterminate(const RenderObject* o) const
 {
-    if (!o->node() || !o->node()->hasTagName(inputTag))
+    if (!isHTMLInputElement(o->node()))
         return false;
     return toHTMLInputElement(o->node())->shouldAppearIndeterminate();
 }
 
 bool RenderTheme::isEnabled(const RenderObject* o) const
 {
     Node* node = o->node();
     if (!node || !node->isElementNode())
         return true;
     return !toElement(node)->isDisabledFormControl();
@@ skipping 125 matching lines @@
 }
 
 bool RenderTheme::paintMeter(RenderObject*, const PaintInfo&, const IntRect&)
 {
     return true;
 }
 
 void RenderTheme::paintSliderTicks(RenderObject* o, const PaintInfo& paintInfo, const IntRect& rect)
 {
     Node* node = o->node();
-    if (!node || !node->hasTagName(inputTag))
+    if (!isHTMLInputElement(node))
         return;
 
     HTMLInputElement* input = toHTMLInputElement(node);
     HTMLDataListElement* dataList = input->dataList();
     if (!dataList)
         return;
 
     double min = input->minimum();
     double max = input->maximum();
     ControlPart part = o->style()->appearance();
@@ skipping 38 matching lines @@
         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; Element* element = options->item(i); i++) {
-        ASSERT(element->hasTagName(optionTag));
-        HTMLOptionElement* optionElement = toHTMLOptionElement(element);
-        String value = optionElement->value();
+        ASSERT(isHTMLOptionElement(*element));
+        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
             tickRect.setY(tickPosition);
@@ skipping 309 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