[SyncFS] Post tasks between SyncEngine and SyncWorker

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/file_util.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
@@ skipping 57 matching lines @@
     ASSERT_TRUE(drive_service->LoadResourceListForWapi(
         "gdata/root_feed.json"));
 
     scoped_ptr<drive::DriveUploaderInterface> uploader(
         new drive::DriveUploader(drive_service.get(),
                                  file_task_runner_.get()));
 
     remote_sync_service_.reset(new SyncEngine(
         drive_service.PassAs<drive::DriveServiceInterface>(),
         uploader.Pass(),
+        file_task_runner_.get(),
         NULL, NULL, NULL));
     remote_sync_service_->AddServiceObserver(this);
     remote_sync_service_->Initialize(
         base_dir_.path(),
-        file_task_runner_.get(),
         in_memory_env_.get());
     remote_sync_service_->SetSyncEnabled(true);
 
     fake_drive_service_helper_.reset(new FakeDriveServiceHelper(
         fake_drive_service(), drive_uploader(),
         kSyncRootFolderTitle));
 
     local_sync_service_->SetLocalChangeProcessor(remote_sync_service_.get());
     remote_sync_service_->SetRemoteChangeProcessor(local_sync_service_.get());
   }
@@ skipping 1486 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