Replace static_cast with safe casting methods

Source/core/svg/SVGFontFaceElement.cpp

 /*
  * Copyright (C) 2007 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2008 Apple Inc. 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.
  *
@@ skipping 289 matching lines @@
 
     if (!list || !list->length())
         return;
 
     // Parse in-memory CSS rules
     m_fontFaceRule->mutableProperties()->addParsedProperty(CSSProperty(CSSPropertySrc, list));
 
     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++) {
             if (CSSFontFaceSrcValue* item = static_cast<CSSFontFaceSrcValue*>(srcList->itemWithoutBoundsCheck(i)))
                 item->setSVGFontFaceElement(this);
         }
     }
 
     document()->styleResolverChanged(DeferRecalcStyle);
 }
@@ skipping 27 matching lines @@
 
 void SVGFontFaceElement::childrenChanged(bool changedByParser, Node* beforeChange, Node* afterChange, int childCountDelta)
 {
     SVGElement::childrenChanged(changedByParser, beforeChange, afterChange, childCountDelta);
     rebuildFontFace();
 }
 
 } // namespace WebCore
 
 #endif // ENABLE(SVG_FONTS)