Implement request id in PaymentDetailsInit

components/payments/content/payment_request.mojom

Index: components/payments/content/payment_request.mojom
diff --git a/components/payments/content/payment_request.mojom b/components/payments/content/payment_request.mojom
index a40f3da2b34b910ed3d4a9899d04a50529a62503..f130861e07f56c3d8c67f41cbfcb88bc6437c6b1 100644
--- a/components/payments/content/payment_request.mojom
+++ b/components/payments/content/payment_request.mojom
@@ -64,6 +64,7 @@ struct PaymentResponse {
   // {"nameOnCard": "Jon Doe", "pan": "4111 1111 1111 1111"}
   string stringified_details;
 
+  string requestId;

[please use gerrit instead, 2017/03/27 16:22:36]

The string is never modified inside of the browser process, so no need to send
it back to the renderer process.

[rwlbuis, 2017/03/27 20:45:29]

Done.

   PaymentAddress? shipping_address;
   string? shipping_option;
   string? payer_name;
@@ -188,6 +189,7 @@ struct PaymentDetails {
   array<PaymentShippingOption> shipping_options;
   array<PaymentDetailsModifier> modifiers;
   string error = "";
+  string? id;

[please use gerrit instead, 2017/03/27 16:22:36]

Add a comment about where this string comes from and how it's going to be used.

[rwlbuis, 2017/03/27 20:45:29]

Done.

 };
 
 enum PaymentShippingType {