Use type cast macro for AnimatableLengthPoint|3D instead of manual toFoo()

Source/core/css/parser/CSSPropertyParser.cpp

Index: Source/core/css/parser/CSSPropertyParser.cpp
diff --git a/Source/core/css/parser/CSSPropertyParser.cpp b/Source/core/css/parser/CSSPropertyParser.cpp
index 600902d0c5d620d408a8946279b8575d687c1c8c..a2b0211ee001dc4e52fc015e9a430a522be97725 100644
--- a/Source/core/css/parser/CSSPropertyParser.cpp
+++ b/Source/core/css/parser/CSSPropertyParser.cpp
@@ -3446,7 +3446,7 @@ bool CSSPropertyParser::parseGridTemplateRowsAndAreas(PassRefPtrWillBeRawPtr<CSS
         if (m_valueList->current()->unit == CSSParserValue::ValueList) {
             if (trailingIdentWasAdded) {
                 // A row's trailing ident must be concatenated with the next row's leading one.
-                parseGridLineNames(*m_valueList, *templateRows, static_cast<CSSGridLineNamesValue*>(templateRows->item(templateRows->length() - 1)));
+                parseGridLineNames(*m_valueList, *templateRows, toCSSGridLineNamesValue(templateRows->item(templateRows->length() - 1)));
             } else {
                 parseGridLineNames(*m_valueList, *templateRows);
             }