Clarify when the user can abort the payment request algorithm (#810)

Author: marcoscaceres

index.html

@@ -4578,13 +4578,13 @@ 
           "PaymentResponse.payerPhone">payerPhonea> value, the user agent
           SHOULD format the phone number to adhere to [[E.164]].
           li>
+          <li>Set <var>requestvar>.<a>[[\state]]a> to "<a>closeda>".
+          li>
           <li>If <var>isRetryvar> is true, resolve
           <var>responsevar>.<a>[[\retryPromise]]a> with undefined.
           Otherwise, resolve <var>requestvar>.<a>[[\acceptPromise]]a> with
           <var>responsevar>.
           li>
-          <li>Set <var>requestvar>.<a>[[\state]]a> to "<a>closeda>".
-          li>
         ol>
       section>
       <section>
@@ -4602,10 +4602,6 @@ 
           <li>Let <var>requestvar> be the <a>PaymentRequesta> object that
           the user is interacting with.
           li>
-          <li>If the <var>requestvar>.<a>[[\updating]]a> is true, then
-          terminate this algorithm and take no further action. The <a>user
-          agenta> user interface SHOULD ensure that this never occurs.
-          li>
           <li>If <var>requestvar>.<a>[[\state]]a> is not
           "<a>interactivea>", then terminate this algorithm and take no
           further action. The <a>user agenta> user interface SHOULD ensure
@@ -4637,6 +4633,9 @@ 
           <li>Otherwise, reject <var>requestvar>.<a>[[\acceptPromise]]a>
           with <var>errorvar>.
           li>
+          <li>Abort the current user interaction and close down any remaining
+          user interface.
+          li>
         ol>
       section>
       <section>
@@ -4654,10 +4653,13 @@ 
           blocked. The user agent SHOULD provide the user with a means to abort
           a payment request. Implementations MAY choose to implement a timeout
           for pending updates if <var>detailsPromisevar> doesn't settle in a
-          reasonable amount of time. If an implementation chooses to implement
-          a timeout, they MUST execute the steps listed below in the "upon
-          rejection" path. Such a timeout is a fatal error for the payment
-          request.
+          reasonable amount of time.
+        p>
+        <p>
+          In the case where a timeout occurs, or the user manually aborts, or
+          the <a>payment handlera> decides to abort this particular payment,
+          the user agent MUST run the <a>user aborts the payment request
+          algorithma>.
         p>
         <ol class="algorithm">
           <li>Set <var>requestvar>.<a>[[\updating]]a> to true.