Move content's shell connections to the IO thread

chrome/test/base/mash_browser_tests_main.cc

Index: chrome/test/base/mash_browser_tests_main.cc
diff --git a/chrome/test/base/mash_browser_tests_main.cc b/chrome/test/base/mash_browser_tests_main.cc
index eeffe524790fdc53d9afc59a42447e1bc3a64207..e415820e317cb02e26f58fc7e58f696510a48ea2 100644
--- a/chrome/test/base/mash_browser_tests_main.cc
+++ b/chrome/test/base/mash_browser_tests_main.cc
@@ -10,6 +10,7 @@
 #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"
@@ -108,7 +109,8 @@ std::unique_ptr<content::MojoShellConnection> CreateMojoShellConnection(
     MashTestLauncherDelegate* delegate) {
   std::unique_ptr<content::MojoShellConnection> connection(
       content::MojoShellConnection::Create(
-          delegate->GetMojoTestConnectorForSingleProcess()->Init()));
+          delegate->GetMojoTestConnectorForSingleProcess()->Init(),
+          base::ThreadTaskRunnerHandle::Get()));
   ConnectToDefaultApps(connection->GetConnector());
   return connection;
 }