[Payment Request] Moves PaymentRequest into the payments namespace

ios/chrome/browser/payments/test_payment_request.mm

Index: ios/chrome/browser/payments/test_payment_request.mm
diff --git a/ios/chrome/browser/payments/test_payment_request.mm b/ios/chrome/browser/payments/test_payment_request.mm
index 21ac0939db2d5580faf776c27d10c755029113e8..953205763010a4c849bcb4a8d6b9d7cb8862d837 100644
--- a/ios/chrome/browser/payments/test_payment_request.mm
+++ b/ios/chrome/browser/payments/test_payment_request.mm
@@ -14,6 +14,8 @@
 #error "This file requires ARC support."
 #endif
 
+namespace payments {
+
 void TestPaymentRequest::ClearShippingProfiles() {
   shipping_profiles_.clear();
 }
@@ -38,8 +40,10 @@ PrefService* TestPaymentRequest::GetPrefService() {
   return PaymentRequest::GetPrefService();
 }
 
-payments::PaymentsProfileComparator* TestPaymentRequest::profile_comparator() {
+PaymentsProfileComparator* TestPaymentRequest::profile_comparator() {
   if (profile_comparator_)
     return profile_comparator_;
   return PaymentRequest::profile_comparator();
 }
+
+}  // namespace payments