[Web Payments] Implement the CVC Unmask dialog.

components/payments/content/payment_request_delegate.h

Index: components/payments/content/payment_request_delegate.h
diff --git a/components/payments/content/payment_request_delegate.h b/components/payments/content/payment_request_delegate.h
index 98040a6aa575dc3d1de708ffcd1ec7e0841cf2d4..360eb8628646a687f1ea510fb4ef7b971481cae5 100644
--- a/components/payments/content/payment_request_delegate.h
+++ b/components/payments/content/payment_request_delegate.h
@@ -7,6 +7,8 @@
 
 #include <string>
 
+#include "components/payments/core/autofill_payment_instrument.h"
+
 namespace autofill {
 class PersonalDataManager;
 }
@@ -15,9 +17,10 @@ namespace payments {
 
 class PaymentRequest;
 
-class PaymentRequestDelegate {
+class PaymentRequestDelegate
+    : public AutofillPaymentInstrument::FullCardRequestDelegate {
  public:
-  virtual ~PaymentRequestDelegate() {}
+  ~PaymentRequestDelegate() override {}
 
   // Shows the Payment Request dialog for the given |request|.
   virtual void ShowDialog(PaymentRequest* request) = 0;