[Payment Request] Refactors the edit view controller

ios/chrome/browser/ui/payments/payment_request_edit_view_controller.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_PAYMENT_REQUEST_EDIT_VIEW_CONTROLLER_H_
 #define IOS_CHROME_BROWSER_UI_PAYMENTS_PAYMENT_REQUEST_EDIT_VIEW_CONTROLLER_H_
 
 #import <UIKit/UIKit.h>
 #include <vector>
 
 #import "ios/chrome/browser/ui/autofill/autofill_ui_type.h"
 #import "ios/chrome/browser/ui/collection_view/collection_view_controller.h"
 #import "ios/chrome/browser/ui/payments/payment_request_edit_view_controller_data_source.h"
 
 extern NSString* const kWarningMessageAccessibilityID;
 
+@class EditorField;
 @class PaymentRequestEditViewController;
 
+// Delegate protocol for PaymentRequestEditViewController.
+@protocol PaymentRequestEditViewControllerDelegate<NSObject>
+
+// Notifies the delegate that the user has selected |field|.
+- (void)paymentRequestEditViewController:
+            (PaymentRequestEditViewController*)controller
+                          didSelectField:(EditorField*)field;
+
+@end
+
 // Validator protocol for PaymentRequestEditViewController.
 @protocol PaymentRequestEditViewControllerValidator<NSObject>
 
-// Returns the validation error string for |value| which has the type
-// |autofillUIType|. |required| indicates whether this is a required field.
-// Returns nil if there are no validation errors.
+// Returns the validation error string for |field|. Returns nil if there are no
+// validation errors.
 - (NSString*)paymentRequestEditViewController:
                  (PaymentRequestEditViewController*)controller
-                                validateValue:(NSString*)value
-                               autofillUIType:(AutofillUIType)autofillUIType
-                                     required:(BOOL)required;
+                                validateField:(EditorField*)field;
 
 @end
 
 // The collection view controller for a generic Payment Request edit screen. It
 // features sections for every EditorField supplied to the initializer. Each
 // section has a text field as well as an error message item which is visible
 // when the value of its respective text field is invalid.
 @interface PaymentRequestEditViewController : CollectionViewController
 
 // The data source for this view controller.
 @property(nonatomic, weak) id<PaymentRequestEditViewControllerDataSource>
     dataSource;
 
+// The delegate to be notified when the user selects an editor field.
+@property(nonatomic, weak) id<PaymentRequestEditViewControllerDelegate>
+    delegate;
+
 // The delegate to be called for validating the fields. By default, the
 // controller is the validator.
 @property(nonatomic, weak) id<PaymentRequestEditViewControllerValidator>
     validatorDelegate;
 
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_PAYMENTS_PAYMENT_REQUEST_EDIT_VIEW_CONTROLLER_H_