Remove unused parameter.

Review URL: https://codereview.chromium.org/1059183004

Cr-Commit-Position: refs/heads/master@{#324141}

content/browser/background_sync/background_sync_manager.cc

@@ -386,20 +386,14 @@ void BackgroundSyncManager::RegisterDidStore(
 
 void BackgroundSyncManager::RemoveRegistrationFromMap(
     int64 sw_registration_id,
-    const std::string& sync_registration_name,
-    BackgroundSyncRegistration* old_registration) {
+    const std::string& sync_registration_name) {
   DCHECK(
       LookupRegistration(sw_registration_id, sync_registration_name, nullptr));
 
   BackgroundSyncRegistrations* registrations =
       &sw_to_registrations_map_[sw_registration_id];
 
-  const auto name_and_registration_iter =
-      registrations->name_to_registration_map.find(sync_registration_name);
-  if (old_registration)
-    *old_registration = name_and_registration_iter->second;
-
-  registrations->name_to_registration_map.erase(name_and_registration_iter);
+  registrations->name_to_registration_map.erase(sync_registration_name);
 }
 
 void BackgroundSyncManager::AddRegistrationToMap(
@@ -455,20 +449,16 @@ void BackgroundSyncManager::UnregisterImpl(
     return;
   }
 
-  BackgroundSyncRegistration old_sync_registration;
-  RemoveRegistrationFromMap(sw_registration_id, sync_registration_name,
-                            &old_sync_registration);
+  RemoveRegistrationFromMap(sw_registration_id, sync_registration_name);
 
   StoreRegistrations(
       origin, sw_registration_id,
       base::Bind(&BackgroundSyncManager::UnregisterDidStore,
-                 weak_ptr_factory_.GetWeakPtr(), sw_registration_id,
-                 old_sync_registration, callback));
+                 weak_ptr_factory_.GetWeakPtr(), sw_registration_id, callback));
 }
 
 void BackgroundSyncManager::UnregisterDidStore(
     int64 sw_registration_id,
-    const BackgroundSyncRegistration& old_sync_registration,
     const StatusCallback& callback,
     ServiceWorkerStatusCode status) {
   if (status == SERVICE_WORKER_ERROR_NOT_FOUND) {

content/browser/background_sync/background_sync_manager.h

@@ -174,11 +174,9 @@ 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,
@@ -209,7 +207,6 @@ class CONTENT_EXPORT BackgroundSyncManager
       const StatusCallback& callback);
   void UnregisterDidStore(
       int64 sw_registration_id,
-      const BackgroundSyncRegistration& old_sync_registration,
       const StatusCallback& callback,
       ServiceWorkerStatusCode status);