mojo: Use TYPE_DEFAULT message-loop for browser-tests.

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/i18n/icu_util.h"
@@ skipping 103 matching lines @@
   std::unique_ptr<content::MojoShellConnection> connection(
       content::MojoShellConnection::Create(
           delegate->GetMojoTestConnectorForSingleProcess()->Init(),
           base::ThreadTaskRunnerHandle::Get()));
   connection->Start();
   ConnectToDefaultApps(connection->GetConnector());
   return connection;
 }
 
 void StartChildApp(shell::mojom::ServiceRequest service_request) {
-  base::MessageLoop message_loop(base::MessageLoop::TYPE_UI);
+  base::MessageLoop message_loop(base::MessageLoop::TYPE_DEFAULT);
   base::RunLoop run_loop;
   mash::MashPackagedService service;
   std::unique_ptr<shell::ServiceContext> context =
       base::MakeUnique<shell::ServiceContext>(&service,
                                               std::move(service_request));
   context->SetConnectionLostClosure(run_loop.QuitClosure());
   service.set_context(std::move(context));
   run_loop.Run();
 }
 
@@ skipping 36 matching lines @@
   content::MojoShellConnection::Factory shell_connection_factory;
   if (command_line.HasSwitch(content::kSingleProcessTestsFlag) &&
       !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);
   return true;
 }