Notification: Implement two-leveled notification.

ui/message_center/views/notification_header_view.h

Index: ui/message_center/views/notification_header_view.h
diff --git a/ui/message_center/views/notification_header_view.h b/ui/message_center/views/notification_header_view.h
new file mode 100644
index 0000000000000000000000000000000000000000..b5fbbc0aa3f3f142394766ade6e3d18d8236918c
--- /dev/null
+++ b/ui/message_center/views/notification_header_view.h
@@ -0,0 +1,57 @@
+// 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 UI_MESSAGE_CENTER_VIEWS_NOTIFICATION_HEADER_VIEW_H_
+#define UI_MESSAGE_CENTER_VIEWS_NOTIFICATION_HEADER_VIEW_H_
+
+#include "base/macros.h"
+#include "ui/message_center/views/padded_button.h"
+#include "ui/views/controls/button/custom_button.h"
+
+namespace views {
+class ImageButton;
+class ImageView;
+class Label;
+}
+
+namespace message_center {
+
+class NotificationHeaderView : public views::CustomButton {
+ public:
+  NotificationHeaderView(views::ButtonListener* listener);
+  void SetAppIcon(const gfx::ImageSkia& img);
+  void SetAppName(const base::string16& name);
+  void SetExpandButtonEnabled(bool enabled);
+  void SetExpanded(bool expanded);
+  void SetSettingsButtonEnabled(bool enabled);
+  void SetCloseButtonEnabled(bool enabled);
+  void SetControlButtonsVisible(bool visible);
+  bool IsExpandButtonEnabled();
+  bool IsSettingsButtonEnabled();
+  bool IsCloseButtonEnabled();
+  bool IsCloseButtonFocused();
+
+  views::ImageButton* expand_button() { return expand_button_; }
+  views::ImageButton* settings_button() { return settings_button_; }
+  views::ImageButton* close_button() { return close_button_; }
+
+ private:
+  void UpdateControlButtonsVisibility();
+
+  views::Label* app_name_view_ = nullptr;
+  views::ImageView* app_icon_view_ = nullptr;
+  views::ImageButton* expand_button_ = nullptr;
+  PaddedButton* settings_button_ = nullptr;
+  PaddedButton* close_button_ = nullptr;
+
+  bool settings_button_enabled_ = false;
+  bool close_button_enabled_ = false;
+  bool is_control_buttons_visible_ = false;
+
+  DISALLOW_COPY_AND_ASSIGN(NotificationHeaderView);
+};
+
+}  // namespace message_center
+
+#endif  // UI_MESSAGE_CENTER_VIEWS_NOTIFICATION_HEADER_VIEW_H_