cros: Initial structure for views-based lock.

ash/login/views/contents_view.h

+// Copyright 2017 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_LOGIN_VIEWS_CONTENTS_VIEW_H_
+#define ASH_LOGIN_VIEWS_CONTENTS_VIEW_H_
+
+#include "base/macros.h"
+#include "ui/views/controls/button/md_text_button.h"
+#include "ui/views/view.h"
+
+namespace ash {
+
+// ContentsView hosts the root view for the lock screen.
+class ContentsView : public views::View, public views::ButtonListener {
+ public:
+  ContentsView();
+  ~ContentsView() override;
+
+  // views::ButtonListener
+  void ButtonPressed(views::Button* sender, const ui::Event& event) override;
+
+ private:
+  views::Button* unlock_button_;
+
+  DISALLOW_COPY_AND_ASSIGN(ContentsView);
+};
+
+}  // ash
+
+#endif  // ASH_LOGIN_VIEWS_CONTENTS_VIEW_H_