Introduce SystemMenuButton for Ash material design

ash/common/system/tray/system_menu_button.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_COMMON_SYSTEM_TRAY_SYSTEM_MENU_BUTTON_H_
+#define ASH_COMMON_SYSTEM_TRAY_SYSTEM_MENU_BUTTON_H_
+
+#include "ash/resources/vector_icons/vector_icons.h"

[James Cook, 2016/09/23 18:32:16]

#include macros.h

[tdanderson, 2016/09/23 19:53:12]

Done.

+#include "ui/views/controls/button/button.h"
+#include "ui/views/controls/button/image_button.h"
+
+namespace views {
+class InkDropHighlight;
+class InkDropRipple;
+}
+
+namespace ash {
+
+class SystemMenuButton : public views::ImageButton {

[James Cook, 2016/09/23 18:32:17]

nit: Class docs. What does this do and why would you choose to use it?

[tdanderson, 2016/09/23 19:53:12]

Slipped my mind, sorry. Done.

+ public:
+  SystemMenuButton(views::ButtonListener* listener,

[James Cook, 2016/09/23 18:32:16]

nit: Document parameters. For example, what sort of ID is |accessible_name_id|?

[tdanderson, 2016/09/23 19:53:12]

Done.

+                   const gfx::VectorIcon& icon,
+                   int accessible_name_id);
+  ~SystemMenuButton() override;
+
+  // views::ImageButton:
+  std::unique_ptr<views::InkDropRipple> CreateInkDropRipple() const override;
+  std::unique_ptr<views::InkDropHighlight> CreateInkDropHighlight()
+      const override;
+  bool ShouldShowInkDropForFocus() const override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SystemMenuButton);
+};
+
+}  // namespace ash
+
+#endif  // ASH_COMMON_SYSTEM_TRAY_SYSTEM_MENU_BUTTON_H_