[SyncFS] Use nullptr for scoped_ptr initialization

chrome/browser/sync_file_system/drive_backend/sync_engine_unittest.cc

 // Copyright 2013 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.
 
 #include "chrome/browser/sync_file_system/drive_backend/sync_engine.h"
 
 #include "base/files/scoped_temp_dir.h"
 #include "base/macros.h"
 #include "base/run_loop.h"
 #include "base/thread_task_runner_handle.h"
@@ skipping 38 matching lines @@
         ui_task_runner.get(),
         worker_task_runner_.get(),
         nullptr /* drive_task_runner */,
         profile_dir_.path(),
         nullptr /* task_logger */,
         nullptr /* notification_manager */,
         nullptr /* extension_service */,
         nullptr /* signin_manager */,
         nullptr /* token_service */,
         nullptr /* request_context */,
-        scoped_ptr<SyncEngine::DriveServiceFactory>(),
+        nullptr /* drive_service_factory */,
         nullptr /* in_memory_env */));
 
     sync_engine_->InitializeForTesting(
         fake_drive_service.Pass(),
-        scoped_ptr<drive::DriveUploaderInterface>(),
+        nullptr,  // drive_uploader
         scoped_ptr<SyncWorkerInterface>(new FakeSyncWorker));
     sync_engine_->SetSyncEnabled(true);
     sync_engine_->OnReadyToSendRequests();
 
     WaitForWorkerTaskRunner();
   }
 
   virtual void TearDown() OVERRIDE {
     sync_engine_.reset();
     WaitForWorkerTaskRunner();
@@ skipping 154 matching lines @@
 TEST_F(SyncEngineTest, ProcessRemoteChange) {
   SyncStatusCode sync_status;
   storage::FileSystemURL url;
   sync_engine()->ProcessRemoteChange(CreateResultReceiver(&sync_status, &url));
   WaitForWorkerTaskRunner();
   EXPECT_EQ(SYNC_STATUS_OK, sync_status);
 }
 
 }  // namespace drive_backend
 }  // namespace sync_file_system