[Mac] Add XPC alerts to GetDisplayedNotifications

content/public/browser/platform_notification_service.h

 // Copyright 2014 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 CONTENT_PUBLIC_BROWSER_PLATFORM_NOTIFICATION_SERVICE_H_
 #define CONTENT_PUBLIC_BROWSER_PLATFORM_NOTIFICATION_SERVICE_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 66 matching lines @@
   virtual void ClosePersistentNotification(
       BrowserContext* browser_context,
       const std::string& notification_id) = 0;
 
   // Writes the ids of all currently displaying notifications for the
   // given |browser_context| to |displayed_notifications|. Returns whether the
   // platform is able to provide such a set.
   virtual bool GetDisplayedNotifications(
       BrowserContext* browser_context,
       std::set<std::string>* displayed_notifications) = 0;
+
+  // Asynchronous version of |GetDisplayedNotifications|
+  // TODO(miguelg) remove the sync version once all paths are ported.
+  virtual void GetDisplayedNotificationsAsync(
+      BrowserContext* browser_context,
+      const base::Callback<void(std::unique_ptr<std::set<std::string>>,
+                                bool /* support sync */)>&) = 0;

[Peter Beverloo, 2017/02/24 16:12:24]

Please define the callback's type with a `using` at the top of this class.

support sync -> whatever you end up with per the other comment

 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_PLATFORM_NOTIFICATION_SERVICE_H_