mojo leveldb: Remove the created file thread.

components/leveldb/leveldb_app.cc

 // Copyright 2016 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 "components/leveldb/leveldb_app.h"
 
 #include "base/message_loop/message_loop.h"
 #include "components/leveldb/leveldb_service_impl.h"
 #include "mojo/shell/public/cpp/connection.h"
 
@@ skipping 10 matching lines @@
 }
 
 bool LevelDBApp::AcceptConnection(mojo::Connection* connection) {
   connection->AddInterface<LevelDBService>(this);
   return true;
 }
 
 void LevelDBApp::Create(mojo::Connection* connection,
                         leveldb::LevelDBServiceRequest request) {
   if (!service_)
-    service_.reset(new LevelDBServiceImpl);
+    service_.reset(
+        new LevelDBServiceImpl(base::MessageLoop::current()->task_runner()));
   bindings_.AddBinding(service_.get(), std::move(request));
 }
 
 }  // namespace leveldb