Change first() and second() in CSSPairValue to return const references

Source/build/scripts/templates/StyleBuilderFunctions.cpp.tmpl

Index: Source/build/scripts/templates/StyleBuilderFunctions.cpp.tmpl
diff --git a/Source/build/scripts/templates/StyleBuilderFunctions.cpp.tmpl b/Source/build/scripts/templates/StyleBuilderFunctions.cpp.tmpl
index 5e050cd7da317259b27de230e895c28afd3c25ba..a45c65b2685e32602ef8224cabe672edfa5d5ba1 100644
--- a/Source/build/scripts/templates/StyleBuilderFunctions.cpp.tmpl
+++ b/Source/build/scripts/templates/StyleBuilderFunctions.cpp.tmpl
@@ -347,8 +347,8 @@ static bool borderImageLengthMatchesAllSides(const BorderImageLengthBox& borderI
     int length = list ? list->length() : 0;
     for (int i = 0; i < length; ++i) {
         const CSSValuePair* pair = toCSSValuePair(list->item(i));
-        AtomicString identifier(toCSSPrimitiveValue(pair->first())->getStringValue());
-        int value = toCSSPrimitiveValue(pair->second())->getIntValue();
+        AtomicString identifier(toCSSPrimitiveValue(pair->first()).getStringValue());
+        int value = toCSSPrimitiveValue(pair->second()).getIntValue();
         CounterDirectives& directives = map.add(identifier, CounterDirectives()).storedValue->value;
         {% if action == 'Reset' %}
         directives.setResetValue(value);