Adds WindowManagerManager to mus

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 d254da5ca1cf887052f47fd39118fd9b96aba0eb..5635d4427a112b4f3febedd745d362541d6510d3 100644
--- a/mash/wm/root_window_controller.h
+++ b/mash/wm/root_window_controller.h
@@ -35,8 +35,6 @@ class WindowManagerApplication;
 class RootWindowController : public mus::WindowObserver,
                              public mus::WindowTreeDelegate {
  public:
-  static RootWindowController* CreateUsingWindowTreeHost(
-      WindowManagerApplication* app);
   static RootWindowController* CreateFromDisplay(
       WindowManagerApplication* app,
       mus::mojom::DisplayPtr display,
@@ -90,8 +88,6 @@ class RootWindowController : public mus::WindowObserver,
 
   scoped_ptr<ShadowController> shadow_controller_;
 
-  mus::mojom::WindowTreeHostPtr window_tree_host_;
-
   mus::mojom::DisplayPtr display_;
 
   DISALLOW_COPY_AND_ASSIGN(RootWindowController);