convert //mash to std::unique_ptr

mash/wm/root_window_controller.h

Index: mash/wm/root_window_controller.h
diff --git a/mash/wm/root_window_controller.h b/mash/wm/root_window_controller.h
index c64eb31cc93bbc3902cbf2fa7e64159a2fc348d9..655a2b584ea996a4bfa1e818b5c563099dbb4e93 100644
--- a/mash/wm/root_window_controller.h
+++ b/mash/wm/root_window_controller.h
@@ -5,6 +5,8 @@
 #ifndef MASH_WM_ROOT_WINDOW_CONTROLLER_H_
 #define MASH_WM_ROOT_WINDOW_CONTROLLER_H_
 
+#include <memory>
+
 #include "components/mus/public/cpp/window_observer.h"
 #include "components/mus/public/cpp/window_tree_delegate.h"
 #include "components/mus/public/interfaces/window_manager_constants.mojom.h"
@@ -86,11 +88,11 @@ class RootWindowController : public mus::WindowObserver,
   mus::Window* root_;
   int window_count_;
 
-  scoped_ptr<WindowManager> window_manager_;
+  std::unique_ptr<WindowManager> window_manager_;
 
-  std::map<mus::Window*, scoped_ptr<LayoutManager>> layout_manager_;
+  std::map<mus::Window*, std::unique_ptr<LayoutManager>> layout_manager_;
 
-  scoped_ptr<ShadowController> shadow_controller_;
+  std::unique_ptr<ShadowController> shadow_controller_;
 
   mus::mojom::DisplayPtr display_;