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

content/browser/push_messaging/push_messaging_router.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_BROWSER_PUSH_MESSAGING_PUSH_MESSAGING_ROUTER_H_
 #define CONTENT_BROWSER_PUSH_MESSAGING_PUSH_MESSAGING_ROUTER_H_
 
 #include <stdint.h>
 
 #include "base/macros.h"
@@ skipping 36 matching lines @@
       const DeliverMessageCallback& deliver_message_callback,
       scoped_refptr<ServiceWorkerContextWrapper> service_worker_context);
 
   // If a registration was successfully retrieved, dispatches a push event with
   // |data| on the Service Worker identified by |service_worker_registration|.
   // Must be called on the IO thread.
   static void FindServiceWorkerRegistrationCallback(
       const PushEventPayload& payload,
       const DeliverMessageCallback& deliver_message_callback,
       ServiceWorkerStatusCode service_worker_status,
-      scoped_refptr<ServiceWorkerRegistration> service_worker_registration);
+      const scoped_refptr<ServiceWorkerRegistration>&
+          service_worker_registration);
 
   // Delivers a push message with |data| to a specific |service_worker|. Must be
   // called on the IO thread, with the the worker running.
   static void DeliverMessageToWorker(
       const scoped_refptr<ServiceWorkerVersion>& service_worker,
       const scoped_refptr<ServiceWorkerRegistration>&
           service_worker_registration,
       const PushEventPayload& payload,
       const DeliverMessageCallback& deliver_message_callback);
 
   // Gets called asynchronously after the Service Worker has dispatched the push
   // event. Must be called on the IO thread.
   static void DeliverMessageEnd(
       const DeliverMessageCallback& deliver_message_callback,
       const scoped_refptr<ServiceWorkerRegistration>&
           service_worker_registration,
       ServiceWorkerStatusCode service_worker_status);
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(PushMessagingRouter);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_PUSH_MESSAGING_PUSH_MESSAGING_ROUTER_H_