[Payments] base::string16 -> std::string in PaymentMethodData

ios/chrome/browser/payments/payment_request_unittest.mm

Index: ios/chrome/browser/payments/payment_request_unittest.mm
diff --git a/ios/chrome/browser/payments/payment_request_unittest.mm b/ios/chrome/browser/payments/payment_request_unittest.mm
index b904821118b03ea1e4f059fa4b3729e0f3a132e8..9fd167bcc2228195f4d29abbca1680fb27d5561a 100644
--- a/ios/chrome/browser/payments/payment_request_unittest.mm
+++ b/ios/chrome/browser/payments/payment_request_unittest.mm
@@ -53,10 +53,10 @@ TEST(PaymentRequestTest, AcceptedPaymentNetworks) {
   autofill::TestPersonalDataManager personal_data_manager;
 
   payments::PaymentMethodData method_datum1;
-  method_datum1.supported_methods.push_back(base::ASCIIToUTF16("visa"));
+  method_datum1.supported_methods.push_back("visa");
   web_payment_request.method_data.push_back(method_datum1);
   payments::PaymentMethodData method_datum2;
-  method_datum2.supported_methods.push_back(base::ASCIIToUTF16("mastercard"));
+  method_datum2.supported_methods.push_back("mastercard");
   web_payment_request.method_data.push_back(method_datum2);
 
   PaymentRequest payment_request(web_payment_request, &personal_data_manager);