[BackgroundSyncManager] Remove dead code

content/browser/background_sync/background_sync_manager.h

Index: content/browser/background_sync/background_sync_manager.h
diff --git a/content/browser/background_sync/background_sync_manager.h b/content/browser/background_sync/background_sync_manager.h
index 2ba2da157216339e53e02e97f9e26398b9be60be..3727be4efe107a6f65af23fb526f596f8b2fdd8d 100644
--- a/content/browser/background_sync/background_sync_manager.h
+++ b/content/browser/background_sync/background_sync_manager.h
@@ -173,11 +173,9 @@ class CONTENT_EXPORT BackgroundSyncManager
                           int64 sw_registration_id,
                           const ServiceWorkerStorage::StatusCallback& callback);
 
-  // If the registration is in the map, removes it and returns the removed
-  // registration in |old_registration|. |old_registration| may be null.
+  // Removes the registration if it is in the map.
   void RemoveRegistrationFromMap(int64 sw_registration_id,
-                                 const std::string& sync_registration_name,
-                                 BackgroundSyncRegistration* old_registration);
+                                 const std::string& sync_registration_name);
 
   void AddRegistrationToMap(
       int64 sw_registration_id,
@@ -208,7 +206,6 @@ class CONTENT_EXPORT BackgroundSyncManager
       const StatusCallback& callback);
   void UnregisterDidStore(
       int64 sw_registration_id,
-      const BackgroundSyncRegistration& old_sync_registration,
       const StatusCallback& callback,
       ServiceWorkerStatusCode status);