mash: Cleanup ash shelf application menu code.

ash/public/cpp/shelf_application_menu_item.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_PUBLIC_CPP_SHELF_APPLICATION_MENU_ITEM_H_
+#define ASH_PUBLIC_CPP_SHELF_APPLICATION_MENU_ITEM_H_
+
+#include <memory>
+#include <vector>
+
+#include "ash/public/cpp/ash_public_export.h"
+#include "base/macros.h"
+#include "base/strings/string16.h"
+#include "ui/gfx/image/image.h"
+
+namespace ash {
+
+// The title, icon, and execute function for shelf application menu items.
+class ASH_PUBLIC_EXPORT ShelfApplicationMenuItem {
+ public:
+  ShelfApplicationMenuItem(const base::string16 title, const gfx::Image* icon);

[James Cook, 2017/02/06 17:30:21]

nit: Note that null icon means empty/no icon.

[msw, 2017/02/07 09:12:01]

Done.

+  virtual ~ShelfApplicationMenuItem();
+
+  // The title and icon for this menu item.
+  const base::string16& title() const { return title_; }
+  const gfx::Image& icon() const { return icon_; }
+
+  // Executes the menu item; |event_flags| can be used to check additional
+  // keyboard modifiers from the event that issued this command.
+  virtual void Execute(int event_flags);

[James Cook, 2017/02/06 17:30:21]

It seems weird to me to have code in ash/public/cpp that has virtual functions.
That implies to me that either chrome implements it and ash calls it, or ash
implements it and chrome calls it, neither of which is allowed in mash.

Why does this live here?

[msw, 2017/02/07 09:12:01]

It is currently implemented by Chrome subclasses, but I aim to change that asap.
I aim to remove this class entirely, and instead use a ContextMenuItem
(generalized to also support application menus) from shelf.mojom. I'll move this
command execution to ShelfItemDelegate's ExecuteCommand function (also
generalized to support application menus in addition to context menus):
https://cs.chromium.org/chromium/src/ash/public/interfaces/shelf.mojom?l=43

+
+ private:
+  const base::string16 title_;
+  const gfx::Image icon_;
+
+  DISALLOW_COPY_AND_ASSIGN(ShelfApplicationMenuItem);
+};
+
+using ShelfApplicationMenuItems =
+    std::vector<std::unique_ptr<ShelfApplicationMenuItem>>;
+
+}  // namespace ash
+
+#endif  // ASH_PUBLIC_CPP_SHELF_APPLICATION_MENU_ITEM_H_