[SyncFS] Implement Database initialization part of SyncEngineInitializer

chrome/browser/sync_file_system/sync_file_system_service_factory.cc

 // Copyright (c) 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/sync_file_system_service_factory.h"
 
 #include "base/command_line.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "chrome/browser/drive/drive_api_service.h"
 #include "chrome/browser/drive/drive_notification_manager_factory.h"
@@ skipping 62 matching lines @@
       kEnableSyncFileSystemV2)) {
     RegisterSyncableFileSystem();
 
     GURL base_drive_url(
         google_apis::DriveApiUrlGenerator::kBaseUrlForProduction);
     GURL base_download_url(
         google_apis::DriveApiUrlGenerator::kBaseDownloadUrlForProduction);
     GURL wapi_base_url(
         google_apis::GDataWapiUrlGenerator::kBaseUrlForProduction);
 
+    scoped_refptr<base::SequencedWorkerPool> worker_pool(
+        content::BrowserThread::GetBlockingPool());
+
     scoped_ptr<drive::DriveAPIService> drive_api_service(
         new drive::DriveAPIService(
             ProfileOAuth2TokenServiceFactory::GetForProfile(profile),
             context->GetRequestContext(),
-            content::BrowserThread::GetBlockingPool(),
+            worker_pool.get(),
             base_drive_url, base_download_url, wapi_base_url,
             std::string() /* custom_user_agent */));
 
     drive::DriveNotificationManager* notification_manager =
         drive::DriveNotificationManagerFactory::GetForProfile(profile);
     ExtensionService* extension_service =
         extensions::ExtensionSystem::Get(profile)->extension_service();
 
+    scoped_refptr<base::SequencedTaskRunner> task_runner(
+        worker_pool->GetSequencedTaskRunnerWithShutdownBehavior(
+            worker_pool->GetSequenceToken(),
+            base::SequencedWorkerPool::SKIP_ON_SHUTDOWN));
+
     scoped_ptr<drive_backend::SyncEngine> sync_engine(
         new drive_backend::SyncEngine(
             context->GetPath(),
+            task_runner.get(),
             drive_api_service.Pass(),
             notification_manager,
             extension_service));
 
     sync_engine->Initialize();
     remote_file_service = sync_engine.PassAs<RemoteFileSyncService>();
   } else {
     // FileSystem needs to be registered before DriveFileSyncService runs
     // its initialization code.
     RegisterSyncableFileSystem();
     remote_file_service =
         DriveFileSyncService::Create(profile).PassAs<RemoteFileSyncService>();
   }
 
   if (CommandLine::ForCurrentProcess()->HasSwitch(kDisableLastWriteWin)) {
     remote_file_service->SetConflictResolutionPolicy(
         CONFLICT_RESOLUTION_POLICY_MANUAL);
   }
 
   service->Initialize(local_file_service.Pass(),
                       remote_file_service.Pass());
   return service;
 }
 
 }  // namespace sync_file_system