Use isSVG*Element() helpers more in SVG code (Part 1)

Source/core/svg/SVGFontData.cpp

Index: Source/core/svg/SVGFontData.cpp
diff --git a/Source/core/svg/SVGFontData.cpp b/Source/core/svg/SVGFontData.cpp
index d1aa25683daa33f078438e3dfcd09e6b12e0f832..325d5479b291a6d2eaa8c8aab16e8436d37b1675 100644
--- a/Source/core/svg/SVGFontData.cpp
+++ b/Source/core/svg/SVGFontData.cpp
@@ -176,8 +176,8 @@ bool SVGFontData::applySVGGlyphSelection(WidthIterator& iterator, GlyphData& gly
         if (Element* parentRenderObjectElement = toElement(parentRenderObject->node())) {
             language = parentRenderObjectElement->getAttribute(XMLNames::langAttr);
 
-            if (parentRenderObjectElement->hasTagName(SVGNames::altGlyphTag)) {
-                if (!toSVGAltGlyphElement(parentRenderObjectElement)->hasValidGlyphElements(altGlyphNames))
+            if (isSVGAltGlyphElement(*parentRenderObjectElement)) {
+                if (!toSVGAltGlyphElement(*parentRenderObjectElement).hasValidGlyphElements(altGlyphNames))
                     altGlyphNames.clear();
             }
         }