[CSS Shapes] polygon y-value calc() args serialize incorrectly

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 94d422a18e6f13550844a5e7674d558a295fc74c..52cfa53182bd1b8344782462e440ce425e25e28d 100644
--- a/Source/core/css/parser/CSSPropertyParser.cpp
+++ b/Source/core/css/parser/CSSPropertyParser.cpp
@@ -4325,14 +4325,15 @@ PassRefPtrWillBeRawPtr<CSSBasicShape> CSSPropertyParser::parseBasicShapePolygon(
 
     CSSParserValue* argumentX = argument;
     while (argumentX) {
+
         if (!validUnit(argumentX, FLength | FPercent))
             return nullptr;
+        RefPtrWillBeRawPtr<CSSPrimitiveValue> xLength = createPrimitiveNumericValue(argumentX);
 
         CSSParserValue* argumentY = args->next();
         if (!argumentY || !validUnit(argumentY, FLength | FPercent))
             return nullptr;
 
-        RefPtrWillBeRawPtr<CSSPrimitiveValue> xLength = createPrimitiveNumericValue(argumentX);
         RefPtrWillBeRawPtr<CSSPrimitiveValue> yLength = createPrimitiveNumericValue(argumentY);
 
         shape->appendPoint(xLength.release(), yLength.release());