[Payments] Use PaymentInstrument/AutofillPaymentInstrument throughout.

components/payments/core/autofill_payment_instrument.h

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_PAYMENTS_CORE_AUTOFILL_PAYMENT_INSTRUMENT_H_
 #define COMPONENTS_PAYMENTS_CORE_AUTOFILL_PAYMENT_INSTRUMENT_H_
 
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/macros.h"
 #include "components/autofill/core/browser/credit_card.h"
 #include "components/payments/core/payment_instrument.h"
 
 namespace autofill {
 class AutofillProfile;
 }
 
 namespace payments {
 
 // Represents an Autofill/Payments credit card form of payment in Payment
 // Request.
 class AutofillPaymentInstrument : public PaymentInstrument {
  public:
   // |billing_profiles| is owned by the caller and should outlive this object.
   AutofillPaymentInstrument(
       const std::string& method_name,
-      const autofill::CreditCard& credit_card,
+      const autofill::CreditCard& card,
       const std::vector<autofill::AutofillProfile*>& billing_profiles,
       const std::string& app_locale);
   ~AutofillPaymentInstrument() override;
 
   // PaymentInstrument:
   void InvokePaymentApp(PaymentInstrument::Delegate* delegate) override;
+  bool IsValid() override;
 
  private:
+  // A copy of the card is owned by this object.
   const autofill::CreditCard credit_card_;
+  // Not owned by this object, should outlive this.
   const std::vector<autofill::AutofillProfile*>& billing_profiles_;
+
   const std::string app_locale_;
 
   DISALLOW_COPY_AND_ASSIGN(AutofillPaymentInstrument);
 };
 
 }  // namespace payments
 
 #endif  // COMPONENTS_PAYMENTS_CORE_AUTOFILL_PAYMENT_INSTRUMENT_H_