[Mac] Add XPC alerts to GetDisplayedNotifications

chrome/browser/notifications/alert_dispatcher_mac.h

 // Copyright 2016 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 CHROME_BROWSER_NOTIFICATIONS_ALERT_DISPATCHER_MAC_H_
 #define CHROME_BROWSER_NOTIFICATIONS_ALERT_DISPATCHER_MAC_H_
 
 #import <Foundation/Foundation.h>
 
+#include "base/callback_forward.h"
+#include "chrome/browser/notifications/displayed_notifications_dispatch_callback.h"
+
 // Interface to communicate with the Alert XPC service.
 @protocol AlertDispatcher<NSObject>
 
 // Deliver a notification to the XPC service to be displayed as an alert.
 - (void)dispatchNotification:(NSDictionary*)data;
 
 // Close a notification for a given |notificationId| and |profileId|.
 - (void)closeNotificationWithId:(NSString*)notificationId
                   withProfileId:(NSString*)profileId;
 
 // Close all notifications.
 - (void)closeAllNotifications;
 
+// Get currently displayed notifications.
+- (void)
+getDisplayedAlertsForProfileId:(NSString*)profileId
+                     incognito:(BOOL)incognito
+            notificationCenter:(NSUserNotificationCenter*)notificationCenter
+                      callback:(GetDisplayedNotificationsCallback)callback;
 @end
 
 #endif  // CHROME_BROWSER_NOTIFICATIONS_ALERT_DISPATCHER_MAC_H_