[Payments] Add support for required fields in editor validation

chrome/browser/ui/views/payments/editor_view_controller.h

Index: chrome/browser/ui/views/payments/editor_view_controller.h
diff --git a/chrome/browser/ui/views/payments/editor_view_controller.h b/chrome/browser/ui/views/payments/editor_view_controller.h
index 14a521aef415a60f42c6b2d8ac79c84baac6cb5b..d9cfed7cb4cbd8a62f556f1583c2a7a337a4858b 100644
--- a/chrome/browser/ui/views/payments/editor_view_controller.h
+++ b/chrome/browser/ui/views/payments/editor_view_controller.h
@@ -34,12 +34,17 @@ struct EditorField {
 
   EditorField(autofill::ServerFieldType type,
               const base::string16& label,

[anthonyvd, 2017/02/13 15:53:53]

Can you add a comment about the parameters? label/required are find but
length_hint is a little obscure.

[Mathieu, 2017/02/13 15:58:15]

Done.

-              LengthHint length_hint)
-      : type(type), label(label), length_hint(length_hint) {}
+              LengthHint length_hint,
+              bool required)
+      : type(type),
+        label(label),
+        length_hint(length_hint),
+        required(required) {}
 
   const autofill::ServerFieldType type;
   const base::string16 label;
   LengthHint length_hint;
+  bool required;
 };
 
 // The PaymentRequestSheetController subtype for the editor screens of the