Removes example code that isn't correctly wired up

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 73 matching lines @@
   }
 
   ::wm::FocusController* focus_controller() { return focus_controller_.get(); }
 
   service_manager::Connector* connector() { return connector_; }
 
   aura::PropertyConverter* property_converter() {
     return property_converter_.get();
   }
 
-  void SetScreenLocked(bool is_locked);
-
   // Creates a new top level window.
   aura::Window* NewTopLevelWindow(
       ui::mojom::WindowType window_type,
       std::map<std::string, std::vector<uint8_t>>* properties);
 
   std::set<RootWindowController*> GetRootWindowControllers();
 
   // Returns the next accelerator namespace id by value in |id|. Returns true
   // if there is another slot available, false if all slots are taken up.
   bool GetNextAcceleratorNamespaceId(uint16_t* id);
@@ skipping 106 matching lines @@
 
   std::unique_ptr<ScreenPositionController> screen_position_controller_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowManager);
 };
 
 }  // namespace mus
 }  // namespace ash
 
 #endif  // ASH_MUS_WINDOW_MANAGER_H_