[Payment Request] Refactors the remaining selector view controllers

ios/chrome/browser/payments/payment_method_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_PAYMENTS_PAYMENT_METHOD_SELECTION_MEDIATOR_H_
+#define IOS_CHROME_BROWSER_PAYMENTS_PAYMENT_METHOD_SELECTION_MEDIATOR_H_
+
+#import "ios/chrome/browser/payments/payment_request_selector_view_controller_data_source.h"
+
+class PaymentRequest;
+
+// Serves as data source for PaymentRequestSelectorViewController.
+@interface PaymentMethodSelectionMediator
+    : NSObject<PaymentRequestSelectorViewControllerDataSource>
+
+// Index for the currently selected item or NSUIntegerMax if there is none.
+@property(nonatomic, readwrite, assign) NSUInteger selectedItemIndex;
+
+// 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. This object will not take ownership of |paymentRequest|.
+- (instancetype)initWithPaymentRequest:(PaymentRequest*)paymentRequest
+    NS_DESIGNATED_INITIALIZER;
+
+- (instancetype)init NS_UNAVAILABLE;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_PAYMENTS_PAYMENT_METHOD_SELECTION_MEDIATOR_H_