Move Show and Hide impls from PlatformWindowMus to NativeWidgetMus

ui/views/mus/platform_window_mus.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 UI_VIEWS_MUS_PLATFORM_WINDOW_MUS_H_
 #define UI_VIEWS_MUS_PLATFORM_WINDOW_MUS_H_
 
 #include <stdint.h>
 
 #include <string>
@@ skipping 23 matching lines @@
 class VIEWS_MUS_EXPORT PlatformWindowMus
     : public NON_EXPORTED_BASE(ui::PlatformWindow),
       public mus::WindowObserver,
       public NON_EXPORTED_BASE(mus::InputEventHandler) {
  public:
   PlatformWindowMus(ui::PlatformWindowDelegate* delegate,
                     shell::Connector* connector,
                     mus::Window* mus_window);
   ~PlatformWindowMus() override;
 
-  void Activate();
-
   void SetCursorById(mus::mojom::Cursor cursor);
 
   // ui::PlatformWindow:
   void Show() override;
   void Hide() override;
   void Close() override;
   void SetBounds(const gfx::Rect& bounds) override;
   gfx::Rect GetBounds() override;
   void SetTitle(const base::string16& title) override;
   void SetCapture() override;
@@ skipping 48 matching lines @@
 #ifndef NDEBUG
   std::unique_ptr<base::WeakPtrFactory<PlatformWindowMus>> weak_factory_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(PlatformWindowMus);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_MUS_PLATFORM_WINDOW_MUS_H_