Revert of Stop passing const-reference of SWRegistration in all GetRegistrationsCallbacks.

content/browser/background_sync/background_sync_manager.h

 // Copyright 2015 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_BROWSER_BACKGROUND_SYNC_BACKGROUND_SYNC_MANAGER_H_
 #define CONTENT_BROWSER_BACKGROUND_SYNC_BACKGROUND_SYNC_MANAGER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 231 matching lines @@
   // FireReadyEvents scans the list of available events and fires those that are
   // ready to fire. For those that can't yet be fired, wakeup alarms are set.
   void FireReadyEvents();
   void FireReadyEventsImpl(const base::Closure& callback);
   void FireReadyEventsDidFindRegistration(
       const std::string& tag,
       BackgroundSyncRegistration::RegistrationId registration_id,
       const base::Closure& event_fired_callback,
       const base::Closure& event_completed_callback,
       ServiceWorkerStatusCode service_worker_status,
-      scoped_refptr<ServiceWorkerRegistration> service_worker_registration);
+      const scoped_refptr<ServiceWorkerRegistration>&
+          service_worker_registration);
   void FireReadyEventsAllEventsFiring(const base::Closure& callback);
 
   // Called when a sync event has completed.
   void EventComplete(
       scoped_refptr<ServiceWorkerRegistration> service_worker_registration,
       int64_t service_worker_id,
       const std::string& tag,
       const base::Closure& callback,
       ServiceWorkerStatusCode status_code);
   void EventCompleteImpl(int64_t service_worker_id,
@@ skipping 42 matching lines @@
   std::unique_ptr<base::Clock> clock_;
 
   base::WeakPtrFactory<BackgroundSyncManager> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BackgroundSyncManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_BACKGROUND_SYNC_BACKGROUND_SYNC_MANAGER_H_