PaymentApp: Add interfaces for implementing InvokePaymentApp().

components/payments/payment_app.mojom

Index: components/payments/payment_app.mojom
diff --git a/components/payments/payment_app.mojom b/components/payments/payment_app.mojom
index a12d53bd3af3dbb9ec9690232ca9fe38aa8822ba..a3e9715b76942776549dc15682ec23d8ceeb5e4d 100644
--- a/components/payments/payment_app.mojom
+++ b/components/payments/payment_app.mojom
@@ -4,6 +4,9 @@
 
 module payments.mojom;
 
+import "components/payments/payment_request.mojom";
+import "url/mojo/url.mojom";
+
 enum PaymentAppManifestError {
   NONE,
   NOT_IMPLEMENTED,
@@ -31,3 +34,11 @@ interface PaymentAppManager {
   GetManifest()
       => (PaymentAppManifest payment_app_manifest, PaymentAppManifestError error);
 };
+
+struct PaymentAppRequestData {
+  url.mojom.Url origin;
+  array<PaymentMethodData> methodData;
+  PaymentItem total;
+  array<PaymentDetailsModifier> modifiers;
+  string optionId;
+};