[Payments] Support canMakePayment on Desktop

components/payments/content/payment_request_state.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_CONTENT_PAYMENT_REQUEST_STATE_H_
 #define COMPONENTS_PAYMENTS_CONTENT_PAYMENT_REQUEST_STATE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 38 matching lines @@
    protected:
     virtual ~Delegate() {}
   };
 
   PaymentRequestState(PaymentRequestSpec* spec,
                       Delegate* delegate,
                       const std::string& app_locale,
                       autofill::PersonalDataManager* personal_data_manager);
   ~PaymentRequestState() override;
 
+  // Returns whether the user has at least one instrument that satisfies the
+  // specified supported payment methods.
+  bool CanMakePayment() const;
   void AddObserver(Observer* observer);
   void RemoveObserver(Observer* observer);
 
   // PaymentInstrument::Delegate:
   void OnInstrumentDetailsReady(
       const std::string& method_name,
       const std::string& stringified_details) override;
   void OnInstrumentDetailsError() override {}
 
   // Initiates the generation of the PaymentResponse. Callers should check
@@ skipping 100 matching lines @@
   std::vector<std::unique_ptr<PaymentInstrument>> available_instruments_;
 
   base::ObserverList<Observer> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(PaymentRequestState);
 };
 
 }  // namespace payments
 
 #endif  // COMPONENTS_PAYMENTS_CONTENT_PAYMENT_REQUEST_STATE_H_