mash: remove more shell/shelf WmWindow usage.

ash/aura/shell_port_classic.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_AURA_SHELL_PORT_CLASSIC_H_
 #define ASH_AURA_SHELL_PORT_CLASSIC_H_
 
 #include <memory>
 
 #include "ash/ash_export.h"
@@ skipping 17 matching lines @@
 
   static ShellPortClassic* Get();
 
   AcceleratorControllerDelegateAura* accelerator_controller_delegate() {
     return accelerator_controller_delegate_.get();
   }
 
   // ShellPort:
   void Shutdown() override;
   Config GetAshConfig() const override;
-  WmWindow* GetPrimaryRootWindow() override;
-  WmWindow* GetRootWindowForDisplayId(int64_t display_id) override;
+  aura::Window* GetPrimaryRootWindow() override;
+  aura::Window* GetRootWindowForDisplayId(int64_t display_id) override;
   const display::ManagedDisplayInfo& GetDisplayInfo(
       int64_t display_id) const override;
   bool IsActiveDisplayId(int64_t display_id) const override;
   display::Display GetFirstDisplay() const override;
   bool IsInUnifiedMode() const override;
   bool IsInUnifiedModeIgnoreMirroring() const override;
   void SetDisplayWorkAreaInsets(WmWindow* window,
                                 const gfx::Insets& insets) override;
   void LockCursor() override;
   void UnlockCursor() override;
@@ skipping 53 matching lines @@
 
   std::unique_ptr<AcceleratorControllerDelegateAura>
       accelerator_controller_delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(ShellPortClassic);
 };
 
 }  // namespace ash
 
 #endif  // ASH_AURA_SHELL_PORT_CLASSIC_H_