Use toSVGFontElement() instead of static_cast<SVGFontElement*>

Source/core/svg/SVGVKernElement.cpp

Index: Source/core/svg/SVGVKernElement.cpp
diff --git a/Source/core/svg/SVGVKernElement.cpp b/Source/core/svg/SVGVKernElement.cpp
index 126023e9d491c9c5ee78ebb33742784f4fb37c4e..d78c777901ca9d19c5d2fbeb8b4ed95487e80b29 100644
--- a/Source/core/svg/SVGVKernElement.cpp
+++ b/Source/core/svg/SVGVKernElement.cpp
@@ -44,10 +44,8 @@ Node::InsertionNotificationRequest SVGVKernElement::insertedInto(ContainerNode*
 {
     if (rootParent->inDocument()) {
         ContainerNode* fontNode = parentNode();
-        if (fontNode && fontNode->hasTagName(SVGNames::fontTag)) {
-            if (SVGFontElement* element = static_cast<SVGFontElement*>(fontNode))
-                element->invalidateGlyphCache();
-        }
+        if (fontNode && fontNode->hasTagName(SVGNames::fontTag))
+            toSVGFontElement(fontNode)->invalidateGlyphCache();
     }
 
     return SVGElement::insertedInto(rootParent);
@@ -56,10 +54,9 @@ Node::InsertionNotificationRequest SVGVKernElement::insertedInto(ContainerNode*
 void SVGVKernElement::removedFrom(ContainerNode* rootParent)
 {
     ContainerNode* fontNode = parentNode();
-    if (fontNode && fontNode->hasTagName(SVGNames::fontTag)) {
-        if (SVGFontElement* element = static_cast<SVGFontElement*>(fontNode))
-            element->invalidateGlyphCache();
-    }
+    if (fontNode && fontNode->hasTagName(SVGNames::fontTag))
+        toSVGFontElement(fontNode)->invalidateGlyphCache();
+
     SVGElement::removedFrom(rootParent);
 }