Introduce isSVGFontElement() and isSVGImageElement(), and use them

Source/core/svg/SVGVKernElement.cpp

 /*
  * 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.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 26 matching lines @@
 
 PassRefPtr<SVGVKernElement> SVGVKernElement::create(const QualifiedName& tagName, Document* document)
 {
     return adoptRef(new SVGVKernElement(tagName, document));
 }
 
 Node::InsertionNotificationRequest SVGVKernElement::insertedInto(ContainerNode* rootParent)
 {
     if (rootParent->inDocument()) {
         ContainerNode* fontNode = parentNode();
-        if (fontNode && fontNode->hasTagName(SVGNames::fontTag))
+        if (fontNode && isSVGFontElement(fontNode))
             toSVGFontElement(fontNode)->invalidateGlyphCache();
     }
 
     return SVGElement::insertedInto(rootParent);
 }
 
 void SVGVKernElement::removedFrom(ContainerNode* rootParent)
 {
     ContainerNode* fontNode = parentNode();
-    if (fontNode && fontNode->hasTagName(SVGNames::fontTag))
+    if (fontNode && isSVGFontElement(fontNode))
         toSVGFontElement(fontNode)->invalidateGlyphCache();
 
     SVGElement::removedFrom(rootParent);
 }
 
 void SVGVKernElement::buildVerticalKerningPair(KerningPairVector& kerningPairs)
 {
     String u1 = fastGetAttribute(SVGNames::u1Attr);
     String g1 = fastGetAttribute(SVGNames::g1Attr);
     String u2 = fastGetAttribute(SVGNames::u2Attr);
     String g2 = fastGetAttribute(SVGNames::g2Attr);
     if ((u1.isEmpty() && g1.isEmpty()) || (u2.isEmpty() && g2.isEmpty()))
         return;
 
     SVGKerningPair kerningPair;
     if (parseGlyphName(g1, kerningPair.glyphName1)
         && parseGlyphName(g2, kerningPair.glyphName2)
         && parseKerningUnicodeString(u1, kerningPair.unicodeRange1, kerningPair.unicodeName1)
         && parseKerningUnicodeString(u2, kerningPair.unicodeRange2, kerningPair.unicodeName2)) {
         kerningPair.kerning = fastGetAttribute(SVGNames::kAttr).string().toFloat();
         kerningPairs.append(kerningPair);
     }
 }
 
 }
 
 #endif // ENABLE(SVG_FONTS)