[Payment Request] Generic edit form

ios/showcase/core/showcase_model.mm

Index: ios/showcase/core/showcase_model.mm
diff --git a/ios/showcase/core/showcase_model.mm b/ios/showcase/core/showcase_model.mm
index 7aafb0c0fc571666956e9e5a197bbd57086400c3..a753a255ba647c694bf2a149d044dad76547af84 100644
--- a/ios/showcase/core/showcase_model.mm
+++ b/ios/showcase/core/showcase_model.mm
@@ -51,6 +51,11 @@
       showcase::kClassForInstantiationKey : @"SCToolbarCoordinator",
       showcase::kUseCaseKey : @"Toolbar",
     },
+    @{
+      showcase::kClassForDisplayKey : @"PaymentRequestEditViewController",
+      showcase::kClassForInstantiationKey : @"SCPaymentsEditorCoordinator",
+      showcase::kUseCaseKey : @"Generic payment request editor",
+    },
   ];
 }