[Payments] Return the preferred payment method name to the merchant

components/payments/content/payment_request_spec.h

Index: components/payments/content/payment_request_spec.h
diff --git a/components/payments/content/payment_request_spec.h b/components/payments/content/payment_request_spec.h
index 729d7ca87e978d8aee6d3adf6884425654b254db..6eff92a56ecbe486500444d50461f33dd4f64b38 100644
--- a/components/payments/content/payment_request_spec.h
+++ b/components/payments/content/payment_request_spec.h
@@ -53,6 +53,10 @@ class PaymentRequestSpec {
   const std::set<std::string>& supported_card_networks_set() const {
     return supported_card_networks_set_;
   }
+  // Returns whether the |method_name| was specified as supported through the
+  // "basic-card" payment method. If false, it means either the |method_name| is
+  // not supported at all, or specified directly in supportedMethods.
+  bool IsMethodSupportedThroughBasicCard(const std::string& method_name);
 
   // Uses CurrencyFormatter to format |amount| with the currency symbol for this
   // request's currency. Will use currency of the "total" display item, because
@@ -95,6 +99,10 @@ class PaymentRequestSpec {
   std::vector<std::string> supported_card_networks_;
   std::set<std::string> supported_card_networks_set_;
 
+  // Only the set of basic-card specified networks. NOTE: callers should use
+  // |supported_card_networks_set_| to check merchant support.
+  std::set<std::string> basic_card_specified_networks_;
+
   base::ObserverList<Observer> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(PaymentRequestSpec);