Revert of Move content's shell connections to the IO thread

chrome/test/base/mash_browser_tests_main.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 <algorithm>
 
 #include "base/at_exit.h"
 #include "base/command_line.h"
 #include "base/debug/debugger.h"
 #include "base/memory/ptr_util.h"
 #include "base/process/launch.h"
 #include "base/sys_info.h"
-#include "base/threading/thread_task_runner_handle.h"
 #include "chrome/test/base/chrome_test_launcher.h"
 #include "chrome/test/base/chrome_test_suite.h"
 #include "chrome/test/base/mojo_test_connector.h"
 #include "content/public/common/mojo_shell_connection.h"
 #include "content/public/test/test_launcher.h"
 #include "services/shell/public/cpp/connector.h"
 #include "services/shell/public/cpp/service.h"
 #include "services/shell/public/cpp/service_context.h"
 #include "services/shell/runner/common/switches.h"
 #include "services/shell/runner/host/child_process.h"
@@ skipping 78 matching lines @@
   std::unique_ptr<shell::Service> service_;
   std::unique_ptr<shell::ServiceContext> shell_connection_;
 
   DISALLOW_COPY_AND_ASSIGN(MashTestLauncherDelegate);
 };
 
 std::unique_ptr<content::MojoShellConnection> CreateMojoShellConnection(
     MashTestLauncherDelegate* delegate) {
   std::unique_ptr<content::MojoShellConnection> connection(
       content::MojoShellConnection::Create(
-          delegate->GetMojoTestConnectorForSingleProcess()->Init(),
-          base::ThreadTaskRunnerHandle::Get()));
-  connection->Start();
+          delegate->GetMojoTestConnectorForSingleProcess()->Init()));
   ConnectToDefaultApps(connection->GetConnector());
   return connection;
 }
 
 }  // namespace
 
 bool RunMashBrowserTests(int argc, char** argv, int* exit_code) {
   base::CommandLine::Init(argc, argv);
   const base::CommandLine& command_line =
       *base::CommandLine::ForCurrentProcess();
@@ skipping 26 matching lines @@
       !command_line.HasSwitch(switches::kPrimordialPipeToken)) {
     shell_connection_factory =
         base::Bind(&CreateMojoShellConnection, &delegate);
     content::MojoShellConnection::SetFactoryForTest(&shell_connection_factory);
   }
   *exit_code = LaunchChromeTests(default_jobs, &delegate, argc, argv);
   // TODO(sky): nuke once resolve why test isn't shutting down: 594600.
   LOG(ERROR) << "RunMashBrowserTests exit_code=" << *exit_code;
   return true;
 }