Use DEFINE_CSS_VALUE_TYPE_CASTS instead of using manual type cast function for CSSShaderValue

Source/core/css/CSSShaderValue.h

Index: Source/core/css/CSSShaderValue.h
diff --git a/Source/core/css/CSSShaderValue.h b/Source/core/css/CSSShaderValue.h
index 69daf55d1fb25fbe598d8b91318760b5b0495385..94816e88571fdec7601c26955465b42fa3c5c997 100644
--- a/Source/core/css/CSSShaderValue.h
+++ b/Source/core/css/CSSShaderValue.h
@@ -64,13 +64,7 @@ private:
     bool m_accessedShader;
 };
 
-// This will catch anyone doing an unnecessary cast.
-CSSShaderValue* toCSSShaderValue(const CSSShaderValue*);
-
-inline CSSShaderValue* toCSSShaderValue(CSSValue* value)
-{
-    return value->isCSSShaderValue() ? static_cast<CSSShaderValue*>(value) : 0;
-}
+DEFINE_CSS_VALUE_TYPE_CASTS(ShaderValue);
 
 } // namespace WebCore