Stop passing const-reference of SWRegistration in all GetRegistrationsCallbacks.

content/browser/background_sync/background_sync_browsertest.cc

Index: content/browser/background_sync/background_sync_browsertest.cc
diff --git a/content/browser/background_sync/background_sync_browsertest.cc b/content/browser/background_sync/background_sync_browsertest.cc
index db7d12ff9389bb69323ec75a826ebbea1f0bdefd..91450a6cef1812de4050e1d52fc611d814651b4d 100644
--- a/content/browser/background_sync/background_sync_browsertest.cc
+++ b/content/browser/background_sync/background_sync_browsertest.cc
@@ -90,7 +90,7 @@ void RegistrationPendingDidGetSWRegistration(
     const std::string& tag,
     const base::Callback<void(bool)>& callback,
     ServiceWorkerStatusCode status,
-    const scoped_refptr<ServiceWorkerRegistration>& registration) {
+    scoped_refptr<ServiceWorkerRegistration> registration) {
   ASSERT_EQ(SERVICE_WORKER_OK, status);
   int64_t service_worker_id = registration->id();
   BackgroundSyncManager* sync_manager = sync_context->background_sync_manager();