Converts mash to use Shell

ash/mus/keyboard_ui_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_KEYBOARD_UI_MUS_H_
 #define ASH_MUS_KEYBOARD_UI_MUS_H_
 
 #include <stdint.h>
 
 #include <memory>
 
 #include "ash/common/keyboard/keyboard_ui.h"
 #include "base/macros.h"
 #include "mojo/public/cpp/bindings/binding.h"
 #include "ui/keyboard/keyboard.mojom.h"
 
 namespace service_manager {
 class Connector;
 }
 
 namespace ash {
 
 class KeyboardUIMus : public KeyboardUI,
                       public keyboard::mojom::KeyboardObserver {
  public:
+  // |connector| may be null in tests.
   explicit KeyboardUIMus(service_manager::Connector* connector);
   ~KeyboardUIMus() override;
 
   static std::unique_ptr<KeyboardUI> Create(
       service_manager::Connector* connector);
 
   // KeyboardUI:
   void Hide() override;
   void Show() override;
   void ShowInDisplay(const int64_t display_id) override;
   bool IsEnabled() override;
 
   // keyboard::mojom::KeyboardObserver:
   void OnKeyboardStateChanged(bool is_enabled,
                               bool is_visible,
                               uint64_t display_id,
                               const gfx::Rect& bounds) override;
 
  private:
   bool is_enabled_;
 
+  // May be null during tests.
   keyboard::mojom::KeyboardPtr keyboard_;
   mojo::Binding<keyboard::mojom::KeyboardObserver> observer_binding_;
 
   DISALLOW_COPY_AND_ASSIGN(KeyboardUIMus);
 };
 
 }  // namespace ash
 
 #endif  // ASH_MUS_KEYBOARD_UI_MUS_H_