Refactors keyboard related code so mash can use a keyboard

chrome/browser/ui/ash/keyboard_ui_service.cc

+// 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.
+
+#include "chrome/browser/ui/ash/keyboard_ui_service.h"
+
+KeyboardUIService::KeyboardUIService() {}
+KeyboardUIService::~KeyboardUIService() {}
+
+void KeyboardUIService::Show() {
+  NOTIMPLEMENTED();
+}
+
+void KeyboardUIService::Hide() {
+  NOTIMPLEMENTED();
+}
+
+void KeyboardUIService::AddObserver(
+    keyboard::mojom::KeyboardObserverPtr observer) {
+  NOTIMPLEMENTED();
+}