chrome: Cleanup class/struct forward declarations

chrome/browser/notifications/notification_display_service.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_NOTIFICATION_DISPLAY_SERVICE_H_
 #define CHROME_BROWSER_NOTIFICATIONS_NOTIFICATION_DISPLAY_SERVICE_H_
 
 #include <set>
 #include <string>
 
 #include "base/macros.h"
 #include "chrome/browser/notifications/notification_common.h"
 #include "components/keyed_service/core/keyed_service.h"
 
 class Notification;
-class NotificationPlatformBridge;
 class Profile;
 
 // Profile-bound service that enables notifications to be displayed and
 // interacted with on the user's screen, orthogonal of whether this
 // functionality is provided by the browser or by the operating system. An
 // instance can be retrieved through the NotificationDisplayServiceFactory.
 //
 // TODO(peter): Add a NotificationHandler mechanism for registering listeners.
 // TODO(miguelg): Remove the SupportsNotificationCenter method.
 class NotificationDisplayService : public KeyedService {
@@ skipping 12 matching lines @@
 
   // Returns whether the implementation can retrieve a list of currently visible
   // notifications and stores them in |*notification_ids| when possible.
   virtual bool GetDisplayed(std::set<std::string>* notifications) const = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(NotificationDisplayService);
 };
 
 #endif  // CHROME_BROWSER_NOTIFICATIONS_NOTIFICATION_DISPLAY_SERVICE_H_