Enable Config::MUS to use classic IME instead of servicified IME.

ash/mus/bridge/shell_port_mash.cc

Index: ash/mus/bridge/shell_port_mash.cc
diff --git a/ash/mus/bridge/shell_port_mash.cc b/ash/mus/bridge/shell_port_mash.cc
index a0024c167ad0ad0f87a32d8bddc714db2a39da7d..9bdd29777468ca58781173f52a738ca9a1a29ce2 100644
--- a/ash/mus/bridge/shell_port_mash.cc
+++ b/ash/mus/bridge/shell_port_mash.cc
@@ -489,6 +489,7 @@ std::unique_ptr<AshWindowTreeHost> ShellPortMash::CreateAshWindowTreeHost(
       window_manager_->window_manager_client()->CreateInitParamsForNewDisplay();
   aura_init_params.display_id = init_params.display_id;
   aura_init_params.display_init_params = std::move(display_params);
+  aura_init_params.use_classic_ime = true;
   return base::MakeUnique<AshWindowTreeHostMus>(std::move(aura_init_params));
 }