[Payments] Use PaymentInstrument/AutofillPaymentInstrument throughout.

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 d205a1bb4abaa69943b93f04c2b67a8eb0f9a344..819ecfb92e59d76142d7845f43870494e9ec270f 100644
--- a/components/payments/content/payment_request_spec.h
+++ b/components/payments/content/payment_request_spec.h
@@ -5,6 +5,7 @@
 #ifndef COMPONENTS_PAYMENTS_CONTENT_PAYMENT_REQUEST_SPEC_H_
 #define COMPONENTS_PAYMENTS_CONTENT_PAYMENT_REQUEST_SPEC_H_
 
+#include <set>
 #include <string>
 #include <vector>
 
@@ -49,6 +50,9 @@ class PaymentRequestSpec {
   const std::vector<std::string>& supported_card_networks() {
     return supported_card_networks_;
   }
+  const std::set<std::string>& supported_card_networks_set() {
+    return supported_card_networks_set_;
+  }
 
   // Uses CurrencyFormatter to format |amount| with the currency symbol for this
   // request's currency. Will use currency of the "total" display item, because
@@ -85,9 +89,11 @@ class PaymentRequestSpec {
   const std::string app_locale_;
   std::unique_ptr<CurrencyFormatter> currency_formatter_;
 
-  // A list of supported basic card networks, in order that they were specified
-  // by the merchant.
+  // A list/set of supported basic card networks. The list is used to keep the
+  // order in which they were specified by the merchant. The set is used for
+  // fast lookup of supported methods.
   std::vector<std::string> supported_card_networks_;
+  std::set<std::string> supported_card_networks_set_;

[Mathieu, 2017/03/16 02:50:03]

this I'm not sure about. It's used in PaymentRequestState when creating the
initial list of instruments. If you have many credit cards, I think the O(1)
lookup will be nice, and it's relatively low overhead to create this set. But I
could see it both ways. WDYT?

[please use gerrit instead, 2017/03/16 14:27:02]

This is OK.

 
   base::ObserverList<Observer> observers_;