Use new is*Element() helper functions in CSS code

Source/core/css/CSSCursorImageValue.cpp

Index: Source/core/css/CSSCursorImageValue.cpp
diff --git a/Source/core/css/CSSCursorImageValue.cpp b/Source/core/css/CSSCursorImageValue.cpp
index fd498ef3c66379959a62a01783ffa55c362d2130..c1ad61210531e22dcb0033d66912eec2bfb75eb4 100644
--- a/Source/core/css/CSSCursorImageValue.cpp
+++ b/Source/core/css/CSSCursorImageValue.cpp
@@ -42,10 +42,7 @@ namespace WebCore {
 static inline SVGCursorElement* resourceReferencedByCursorElement(const String& url, Document& document)
 {
     Element* element = SVGURIReference::targetElementFromIRIString(url, document);
-    if (element && element->hasTagName(SVGNames::cursorTag))
-        return toSVGCursorElement(element);
-
-    return 0;
+    return isSVGCursorElement(element) ? toSVGCursorElement(element) : 0;
 }
 
 CSSCursorImageValue::CSSCursorImageValue(PassRefPtrWillBeRawPtr<CSSValue> imageValue, bool hasHotSpot, const IntPoint& hotSpot)