Introduce toSVGGlyphElement(), toSVGHKernElement() and toSVGVKernElement(), and use them

Source/core/svg/SVGFontElement.cpp

 /*
  * Copyright (C) 2007 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  *
  * 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 106 matching lines @@
 
 void SVGFontElement::ensureGlyphCache()
 {
     if (m_isGlyphCacheValid)
         return;
 
     SVGMissingGlyphElement* firstMissingGlyphElement = 0;
     Vector<String> ligatures;
     for (Node* child = firstChild(); child; child = child->nextSibling()) {
         if (child->hasTagName(SVGNames::glyphTag)) {
-            SVGGlyphElement* glyph = static_cast<SVGGlyphElement*>(child);
+            SVGGlyphElement* glyph = toSVGGlyphElement(child);
             AtomicString unicode = glyph->fastGetAttribute(SVGNames::unicodeAttr);
             AtomicString glyphId = glyph->getIdAttribute();
             if (glyphId.isEmpty() && unicode.isEmpty())
                 continue;
 
             m_glyphMap.addGlyph(glyphId, unicode, glyph->buildGlyphIdentifier());
 
             // Register ligatures, if needed, don't mix up with surrogate pairs though!
             if (unicode.length() > 1 && !U16_IS_SURROGATE(unicode[0]))
                 ligatures.append(unicode.string());
         } else if (child->hasTagName(SVGNames::hkernTag)) {
-            SVGHKernElement* hkern = static_cast<SVGHKernElement*>(child);
-            hkern->buildHorizontalKerningPair(m_horizontalKerningPairs);
+            toSVGHKernElement(child)->buildHorizontalKerningPair(m_horizontalKerningPairs);
         } else if (child->hasTagName(SVGNames::vkernTag)) {
-            SVGVKernElement* vkern = static_cast<SVGVKernElement*>(child);
-            vkern->buildVerticalKerningPair(m_verticalKerningPairs);
+            toSVGVKernElement(child)->buildVerticalKerningPair(m_verticalKerningPairs);
         } else if (child->hasTagName(SVGNames::missing_glyphTag) && !firstMissingGlyphElement) {
             firstMissingGlyphElement = toSVGMissingGlyphElement(child);
         }
     }
 
     // Register each character of each ligature, if needed.
     if (!ligatures.isEmpty())
         registerLigaturesInGlyphCache(ligatures);
 
     // Register missing-glyph element, if present.
@@ skipping 100 matching lines @@
 
 Glyph SVGFontElement::missingGlyph()
 {
     ensureGlyphCache();
     return m_missingGlyph;
 }
 
 }
 
 #endif // ENABLE(SVG_FONTS)