[SyncFS] Remove using MessageLoop in worker thread

chrome/browser/sync_file_system/drive_backend/conflict_resolver_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/conflict_resolver.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/file_util.h"
 #include "base/files/scoped_temp_dir.h"
@@ skipping 75 matching lines @@
     sync_task_manager_.reset();
     RevokeSyncableFileSystem();
     fake_drive_helper_.reset();
     context_.reset();
     base::RunLoop().RunUntilIdle();
   }
 
   void InitializeMetadataDatabase() {
     SyncEngineInitializer* initializer =
         new SyncEngineInitializer(context_.get(),
-                                  base::MessageLoopProxy::current(),
                                   database_dir_.path(),
                                   in_memory_env_.get());
     SyncStatusCode status = SYNC_STATUS_UNKNOWN;
     sync_task_manager_->ScheduleSyncTask(
         FROM_HERE,
         scoped_ptr<SyncTask>(initializer),
         SyncTaskManager::PRIORITY_MED,
         base::Bind(&ConflictResolverTest::DidInitializeMetadataDatabase,
                    base::Unretained(this), initializer, &status));
 
@@ skipping 406 matching lines @@
 
   EXPECT_EQ(4, CountParents(file));
 
   EXPECT_EQ(SYNC_STATUS_OK, RunConflictResolver());
 
   EXPECT_EQ(1, CountParents(file));
 }
 
 }  // namespace drive_backend
 }  // namespace sync_file_system