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