[Web Payments] Implement the CVC Unmask dialog.

components/payments/content/payment_request_state.h

Index: components/payments/content/payment_request_state.h
diff --git a/components/payments/content/payment_request_state.h b/components/payments/content/payment_request_state.h
index 11dc00f84151019a48596d36ec5f9d8dfc9eb3d8..934fbbcb8c595b20a5d506bc140598f53a9d71f2 100644
--- a/components/payments/content/payment_request_state.h
+++ b/components/payments/content/payment_request_state.h
@@ -21,6 +21,7 @@ class PersonalDataManager;
 namespace payments {
 
 class PaymentRequestSpec;
+class PaymentRequestDelegate;
 
 // Keeps track of the information currently selected by the user and whether the
 // user is ready to pay. Uses information from the PaymentRequestSpec, which is
@@ -45,6 +46,7 @@ class PaymentRequestState : public PaymentInstrument::Delegate {
     // Called when the PaymentResponse is available.
     virtual void OnPaymentResponseAvailable(
         mojom::PaymentResponsePtr response) = 0;
+    virtual PaymentRequestDelegate* GetPaymentRequestDelegate() = 0;
 
    protected:
     virtual ~Delegate() {}
@@ -116,6 +118,8 @@ class PaymentRequestState : public PaymentInstrument::Delegate {
   const std::string& GetApplicationLocale();
   autofill::PersonalDataManager* GetPersonalDataManager();
 
+  Delegate* delegate() { return delegate_; }
+
  private:
   // Fetches the Autofill Profiles for this user from the PersonalDataManager,
   // and stores copies of them, owned by this PaymentRequestState, in