[SyncFS] Use nullptr for scoped_ptr initialization

chrome/browser/sync_file_system/drive_backend/drive_backend_sync_unittest.cc

 // 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.
 
 #include <algorithm>
 #include <stack>
 
 #include "base/files/file_util.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
@@ skipping 107 matching lines @@
         new SyncEngine(base::ThreadTaskRunnerHandle::Get(),  // ui_task_runner
                        worker_task_runner_.get(),
                        drive_task_runner.get(),
                        base_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
                        in_memory_env_.get()));
     remote_sync_service_->AddServiceObserver(this);
     remote_sync_service_->InitializeForTesting(
         drive_service.PassAs<drive::DriveServiceInterface>(),
-        uploader.Pass(),
-        scoped_ptr<SyncWorkerInterface>());
+        uploader.Pass(), nullptr /* sync_worker */);
     remote_sync_service_->SetSyncEnabled(true);
 
     local_sync_service_->SetLocalChangeProcessor(remote_sync_service_.get());
     remote_sync_service_->SetRemoteChangeProcessor(local_sync_service_.get());
   }
 
   virtual void TearDown() OVERRIDE {
     typedef std::map<std::string, CannedSyncableFileSystem*>::iterator iterator;
     for (iterator itr = file_systems_.begin();
          itr != file_systems_.end(); ++itr) {
@@ skipping 1577 matching lines @@
 
   EXPECT_EQ(1u, CountApp());
   EXPECT_EQ(1u, CountLocalFile(app_id));
 
   EXPECT_EQ(2u, CountMetadata());
   EXPECT_EQ(2u, CountTracker());
 }
 
 }  // namespace drive_backend
 }  // namespace sync_file_system