Revert Change ServiceManagerConnectionImpl to run service request handlers on the IO thread

content/common/service_manager/service_manager_connection_impl_unittest.cc

-// Copyright 2017 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 "content/common/service_manager/service_manager_connection_impl.h"
-
-#include "base/message_loop/message_loop.h"
-#include "base/synchronization/waitable_event.h"
-#include "base/threading/thread.h"
-#include "services/service_manager/public/cpp/identity.h"
-#include "services/service_manager/public/cpp/service.h"
-#include "services/service_manager/public/interfaces/constants.mojom.h"
-#include "services/service_manager/public/interfaces/service_factory.mojom.h"
-#include "testing/gtest/include/gtest/gtest.h"
-
-namespace content {
-namespace {
-
-constexpr char kTestServiceName[] = "test service";
-
-std::unique_ptr<service_manager::Service> LaunchService(
-    base::WaitableEvent* event) {
-  event->Signal();
-  return base::MakeUnique<service_manager::Service>();
-}
-
-}  // namespace
-
-TEST(ServiceManagerConnectionImplTest, ServiceLaunchThreading) {
-  base::MessageLoop message_loop;
-  base::Thread io_thread("ServiceManagerConnectionImplTest IO Thread");
-  io_thread.Start();
-  service_manager::mojom::ServicePtr service;
-  ServiceManagerConnectionImpl connection_impl(mojo::MakeRequest(&service),
-                                               io_thread.task_runner());
-  ServiceManagerConnection& connection = connection_impl;
-  ServiceInfo info;
-  base::WaitableEvent event(base::WaitableEvent::ResetPolicy::MANUAL,
-                            base::WaitableEvent::InitialState::NOT_SIGNALED);
-  info.factory = base::Bind(&LaunchService, &event);
-  info.task_runner = io_thread.task_runner();
-  connection.AddEmbeddedService(kTestServiceName, info);
-  connection.Start();
-  service_manager::ServiceInfo source_info(
-      {service_manager::mojom::kServiceName,
-       service_manager::mojom::kRootUserID},
-      service_manager::InterfaceProviderSpecMap{});
-  service_manager::mojom::ServiceFactoryPtr factory;
-  service->OnBindInterface(source_info,
-                           service_manager::mojom::ServiceFactory::Name_,
-                           mojo::MakeRequest(&factory).PassMessagePipe(),
-                           base::Bind(&base::DoNothing));
-  service_manager::mojom::ServicePtr created_service;
-  factory->CreateService(mojo::MakeRequest(&created_service), kTestServiceName);
-  event.Wait();
-}
-
-}  // namespace content