Refactors keyboard related code so mash can use a keyboard

ash/keyboard/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_KEYBOARD_KEYBOARD_UI_MUS_H_
+#define ASH_KEYBOARD_KEYBOARD_UI_MUS_H_
+
+#include "ash/keyboard/keyboard_ui.h"
+#include "base/macros.h"
+#include "mojo/public/cpp/bindings/binding.h"
+#include "ui/keyboard/keyboard.mojom.h"
+
+namespace ash {
+
+class KeyboardUIMus : public KeyboardUI,
+                      public keyboard::mojom::KeyboardObserver {
+ public:
+  KeyboardUIMus();
+  ~KeyboardUIMus() override;
+
+  // KeyboardUI:
+  void Hide() override;
+  void Show() override;
+  bool IsEnabled() override;
+
+  // keyboard::mojom::KeyboardObserver:
+  void OnKeyboardStateChanged(bool is_enabled,
+                              bool is_visible,
+                              uint64_t display_id,
+                              mojo::RectPtr bounds) override;
+
+ private:
+  bool is_enabled_;
+
+  keyboard::mojom::KeyboardPtr keyboard_;
+  mojo::Binding<keyboard::mojom::KeyboardObserver> observer_binding_;
+
+  DISALLOW_COPY_AND_ASSIGN(KeyboardUIMus);
+};
+
+}  // namespace ash
+
+#endif  // ASH_KEYBOARD_KEYBOARD_UI_MUS_H_