Replace static_cast with safe casting methods

Source/core/svg/SVGFontFaceElement.cpp

Index: Source/core/svg/SVGFontFaceElement.cpp
diff --git a/Source/core/svg/SVGFontFaceElement.cpp b/Source/core/svg/SVGFontFaceElement.cpp
index 40c41683de1a1ae8f9dac37bc245c29264842291..eca164117fd71c6dbca415e42da6660054163415 100644
--- a/Source/core/svg/SVGFontFaceElement.cpp
+++ b/Source/core/svg/SVGFontFaceElement.cpp
@@ -307,7 +307,7 @@ void SVGFontFaceElement::rebuildFontFace()
     if (describesParentFont) {
         // Traverse parsed CSS values and associate CSSFontFaceSrcValue elements with ourselves.
         RefPtr<CSSValue> src = m_fontFaceRule->properties()->getPropertyCSSValue(CSSPropertySrc);
-        CSSValueList* srcList = static_cast<CSSValueList*>(src.get());
+        CSSValueList* srcList = toCSSValueList(src.get());
 
         unsigned srcLength = srcList ? srcList->length() : 0;
         for (unsigned i = 0; i < srcLength; i++) {