Removes WmRootWindowController subclasses

ash/mus/bridge/wm_window_mus.h

 // Copyright 2016 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_BRIDGE_WM_WINDOW_MUS_H_
 #define ASH_MUS_BRIDGE_WM_WINDOW_MUS_H_
 
 #include <memory>
 
 #include "ash/aura/wm_window_aura.h"
 #include "base/macros.h"
 
 namespace aura {
 class Window;
 }
 
 namespace views {
 class Widget;
 }
 
 namespace ash {
 namespace mus {
 
-class WmRootWindowControllerMus;
-
 // WmWindow implementation for mus.
 //
 // WmWindowMus is tied to the life of the underlying aura::Window (it is stored
 // as an owned property).
 class WmWindowMus : public WmWindowAura {
  public:
   explicit WmWindowMus(aura::Window* window);
   // NOTE: this class is owned by the corresponding window. You shouldn't delete
   // TODO(sky): friend deleter and make private.
   ~WmWindowMus() override;
 
   // Returns a WmWindow for an aura::Window, creating if necessary.
   static WmWindowMus* Get(aura::Window* window) {
     return const_cast<WmWindowMus*>(
         Get(const_cast<const aura::Window*>(window)));
   }
   static const WmWindowMus* Get(const aura::Window* window);
 
   static WmWindowMus* Get(views::Widget* widget);
 
-  WmRootWindowControllerMus* GetRootWindowControllerMus() {
-    return const_cast<WmRootWindowControllerMus*>(
-        const_cast<const WmWindowMus*>(this)->GetRootWindowControllerMus());
-  }
-  const WmRootWindowControllerMus* GetRootWindowControllerMus() const;
-
   static WmWindowMus* AsWmWindowMus(WmWindow* window) {
     return static_cast<WmWindowMus*>(window);
   }
   static const WmWindowMus* AsWmWindowMus(const WmWindow* window) {
     return static_cast<const WmWindowMus*>(window);
   }
 
   // Returns true if this window is considered a shell window container.
   bool IsContainer() const;
 
   // WmWindow:
-  WmRootWindowController* GetRootWindowController() override;
   WmShell* GetShell() const override;
   void CloseWidget() override;
   void AddLimitedPreTargetHandler(ui::EventHandler* handler) override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(WmWindowMus);
 };
 
 }  // namespace mus
 }  // namespace ash
 
 #endif  // ASH_MUS_BRIDGE_WM_WINDOW_MUS_H_