[Payment Request] Moves PaymentRequest into the payments namespace

ios/chrome/browser/ui/payments/billing_address_selection_mediator.h

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef IOS_CHROME_BROWSER_UI_PAYMENTS_BILLING_ADDRESS_SELECTION_MEDIATOR_H_
 #define IOS_CHROME_BROWSER_UI_PAYMENTS_BILLING_ADDRESS_SELECTION_MEDIATOR_H_
 
 #import "ios/chrome/browser/ui/payments/payment_request_selector_view_controller_data_source.h"
 
-class PaymentRequest;
-
 namespace autofill {
 class AutofillProfile;
 }  // namespace autofill
 
+namespace payments {
+class PaymentRequest;
+}  // namespace payments
+
 // Serves as data source for PaymentRequestSelectorViewController.
 @interface BillingAddressSelectionMediator
     : NSObject<PaymentRequestSelectorViewControllerDataSource>
 
 // Redefined to be read-write.
 @property(nonatomic, readwrite, assign) PaymentRequestSelectorState state;
 
 // Redefined to be read-write.
 @property(nonatomic, readwrite, assign) NSUInteger selectedItemIndex;
 
 // Creates and stores the selectable items to display in the collection.
 - (void)loadItems;
 
 // Initializes this object with an instance of PaymentRequest which has a copy
 // of web::PaymentRequest as provided by the page invoking the Payment Request
 // API as well as the selected billing profile. This object will not take
 // ownership of |paymentRequest| or |selectedBillingProfile|.
-- (instancetype)initWithPaymentRequest:(PaymentRequest*)paymentRequest
+- (instancetype)initWithPaymentRequest:(payments::PaymentRequest*)paymentRequest
                 selectedBillingProfile:
                     (autofill::AutofillProfile*)selectedBillingProfile
     NS_DESIGNATED_INITIALIZER;
 
 - (instancetype)init NS_UNAVAILABLE;
 
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_PAYMENTS_BILLING_ADDRESS_SELECTION_MEDIATOR_H_