Make PaymentItem.type nullable

Author: marcoscaceres

index.html

@@ -1854,7 +1854,7 @@ 
           required DOMString label;
           required PaymentCurrencyAmount amount;
           boolean pending = false;
-          PaymentItemType type;
+          PaymentItemType? type;
         };
       pre>
       <p>
@@ -1891,10 +1891,11 @@ 
           <dfn>typedfn> member
         dt>
         <dd>
-          A <a>PaymentItemTypea> enum value. A the value of <a>typea> to
-          assist in the presentation of <a>PaymentItema> by, for example,
-          visually grouping types together or other otherwise distinguishing
-          them from other types (or from items that have no associated type).
+          A <a>PaymentItemTypea> enum value or null. A user agent MAY use the
+          value of <a>typea> to assist in the presentation of
+          <a>PaymentItema> by, for example, visually grouping types together
+          or other otherwise distinguishing them from other types (or from
+          items that have no associated type).
         dd>
       dl>
     section>