[Payment Request] Selector view controller

ios/chrome/browser/payments/payment_request_selector_view_controller_data_source.h

Index: ios/chrome/browser/payments/payment_request_selector_view_controller_data_source.h
diff --git a/ios/chrome/browser/payments/payment_request_selector_view_controller_data_source.h b/ios/chrome/browser/payments/payment_request_selector_view_controller_data_source.h
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+++ b/ios/chrome/browser/payments/payment_request_selector_view_controller_data_source.h
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+// 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_REQUEST_SELECTOR_VIEW_CONTROLLER_DATA_SOURCE_H_
+#define IOS_CHROME_BROWSER_PAYMENTS_PAYMENT_REQUEST_SELECTOR_VIEW_CONTROLLER_DATA_SOURCE_H_
+
+#import <Foundation/Foundation.h>
+
+#import "ios/chrome/browser/ui/collection_view/cells/collection_view_item.h"
+#import "ios/chrome/browser/ui/collection_view/collection_view_model.h"
+
+// These are the item types implementations of this protocol must use for the
+// header item and the selectable items respectively.
+const NSInteger kItemTypeHeaderItem = kItemTypeEnumZero;
+const NSInteger kItemTypeSelectableItem = kItemTypeHeaderItem + 1;
+
+// The possible states the view controller can be in.
+typedef NS_ENUM(NSUInteger, PaymentRequestSelectorState) {
+  // The view controller is in normal state.
+  PaymentRequestSelectorStateNormal,
+  // The view controller is in pending state.
+  PaymentRequestSelectorStatePending,
+  // The view controller is in error state.
+  PaymentRequestSelectorStateError,
+};
+
+// The data source for the PaymentRequestSelectorViewController. The data
+// source provides the UI models for the PaymentRequestSelectorViewController
+// to display and keeps track of the selected UI model, if any.
+@protocol PaymentRequestSelectorViewControllerDataSource<NSObject>
+
+// The current state of the view controller.
+@property(nonatomic, readonly) PaymentRequestSelectorState state;
+
+// Index for the currently selected item or NSUIntegerMax if there is none.
+@property(nonatomic, readonly) NSUInteger selectedItemIndex;
+
+// The header item to display in the collection, if any.
+- (CollectionViewItem*)headerItem;
+
+// The selectable items to display in the collection.
+- (NSArray<CollectionViewItem*>*)selectableItems;
+
+// The selectable item at |index| in the collection.
+- (CollectionViewItem*)selectableItemAtIndex:(NSUInteger)index;
+
+// Title for the add button. if nil, no add button should be displayed.
+- (NSString*)addButtonTitle;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_PAYMENTS_PAYMENT_REQUEST_SELECTOR_VIEW_CONTROLLER_DATA_SOURCE_H_