chromeos: turn on simplified display management for mash

ash/mus/window_manager.cc

Index: ash/mus/window_manager.cc
diff --git a/ash/mus/window_manager.cc b/ash/mus/window_manager.cc
index b9ea19ffd9acbc2c53ecfacc424a3850b8998d45..cc4d043754d6cce10ca6e68e293329934f1b29d4 100644
--- a/ash/mus/window_manager.cc
+++ b/ash/mus/window_manager.cc
@@ -127,7 +127,7 @@ void WindowManager::Init(
   ash::Shell::set_window_tree_client(window_tree_client_.get());
 
   // TODO(sky): remove and use MUS code.
-  if (config_ == Config::MASH) {
+  if (!Shell::ShouldEnableSimplifiedDisplayManagement(config_)) {
     // |connector_| is null in some tests.
     if (connector_)
       connector_->BindInterface(ui::mojom::kServiceName, &display_controller_);
@@ -335,7 +335,7 @@ void WindowManager::SetWindowManagerClient(aura::WindowManagerClient* client) {
 }
 
 void WindowManager::OnWmConnected() {
-  if (config_ != Config::MUS)
+  if (!Shell::ShouldEnableSimplifiedDisplayManagement(config_))
     return;
 
   CreateShell(nullptr);