[Payment Request] Moves PaymentRequest into the payments namespace

ios/chrome/browser/ui/payments/payment_request_mediator.mm

Index: ios/chrome/browser/ui/payments/payment_request_mediator.mm
diff --git a/ios/chrome/browser/ui/payments/payment_request_mediator.mm b/ios/chrome/browser/ui/payments/payment_request_mediator.mm
index 6add498432daffc4b383f31cda9eb64c8da4db3b..f760154d2cbfe9d6d1d68092fad779e8c5103ec7 100644
--- a/ios/chrome/browser/ui/payments/payment_request_mediator.mm
+++ b/ios/chrome/browser/ui/payments/payment_request_mediator.mm
@@ -54,7 +54,7 @@ using ::payment_request_util::GetShippingSectionTitle;
 // The PaymentRequest object owning an instance of web::PaymentRequest as
 // provided by the page invoking the Payment Request API. This is a weak
 // pointer and should outlive this class.
-@property(nonatomic, assign) PaymentRequest* paymentRequest;
+@property(nonatomic, assign) payments::PaymentRequest* paymentRequest;
 
 @end
 
@@ -63,7 +63,8 @@ using ::payment_request_util::GetShippingSectionTitle;
 @synthesize totalValueChanged = _totalValueChanged;
 @synthesize paymentRequest = _paymentRequest;
 
-- (instancetype)initWithPaymentRequest:(PaymentRequest*)paymentRequest {
+- (instancetype)initWithPaymentRequest:
+    (payments::PaymentRequest*)paymentRequest {
   self = [super init];
   if (self) {
     _paymentRequest = paymentRequest;