Revert of chromeos: Makes mushrome use simplified display management

ash/mus/window_manager.h

Index: ash/mus/window_manager.h
diff --git a/ash/mus/window_manager.h b/ash/mus/window_manager.h
index 84bb75f6b0985fe880f278558bbd2ad01fe66cb8..8f8631b130d1f85b0c49c0f0e3341d0a24a8cc75 100644
--- a/ash/mus/window_manager.h
+++ b/ash/mus/window_manager.h
@@ -68,11 +68,7 @@
 class WindowManager : public aura::WindowManagerDelegate,
                       public aura::WindowTreeClientDelegate {
  public:
-  // Set |show_primary_host_on_connect| to true if the initial display should
-  // be made visible.  Generally tests should use false, other places use true.
-  WindowManager(service_manager::Connector* connector,
-                Config config,
-                bool show_primary_host_on_connect);
+  WindowManager(service_manager::Connector* connector, Config config);
   ~WindowManager() override;
 
   void Init(std::unique_ptr<aura::WindowTreeClient> window_tree_client,
@@ -206,8 +202,6 @@
 
   const Config config_;
 
-  const bool show_primary_host_on_connect_;
-
   base::OnceClosure lost_connection_callback_;
 
   std::unique_ptr<::wm::WMState> wm_state_;