mash: remove more shell/shelf WmWindow usage.

ash/mus/window_manager.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ASH_MUS_WINDOW_MANAGER_H_
 #define ASH_MUS_WINDOW_MANAGER_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 127 matching lines @@
       const display::Display& display,
       ash::RootWindowController::RootWindowType root_window_type);
 
   // Deletes the specified RootWindowController. Called when a display is
   // removed. |in_shutdown| is true if called from Shutdown().
   void DestroyRootWindowController(RootWindowController* root_window_controller,
                                    bool in_shutdown);
 
   void Shutdown();
 
-  RootWindowController* GetPrimaryRootWindowController();
-
   // WindowTreeClientDelegate:
   void OnEmbed(
       std::unique_ptr<aura::WindowTreeHostMus> window_tree_host) override;
   void OnEmbedRootDestroyed(aura::WindowTreeHostMus* window_tree_host) override;
   void OnLostConnection(aura::WindowTreeClient* client) override;
   void OnPointerEventObserved(const ui::PointerEvent& event,
                               aura::Window* target) override;
   aura::PropertyConverter* GetPropertyConverter() override;
 
   // WindowManagerDelegate:
@@ skipping 82 matching lines @@
 
   std::unique_ptr<ui::InputDeviceClient> input_device_client_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowManager);
 };
 
 }  // namespace mus
 }  // namespace ash
 
 #endif  // ASH_MUS_WINDOW_MANAGER_H_