fix: fallback to GtkStatusIcon when app indicator is not supported (#36815)

* chore: get ready for multi backend tray

* fix: fallback to GtkStatusIcon when app indicator is not supported

* chore: use smart pointers

shell/browser/ui/gtk/menu_gtk.h

@@ -0,0 +1,48 @@
+// Copyright 2014 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 ELECTRON_SHELL_BROWSER_UI_GTK_MENU_GTK_H_
+#define ELECTRON_SHELL_BROWSER_UI_GTK_MENU_GTK_H_
+
+#include "base/callback.h"
+#include "base/memory/raw_ptr.h"
+#include "ui/base/glib/glib_signal.h"
+#include "ui/base/glib/scoped_gobject.h"
+
+typedef struct _GtkMenu GtkMenu;
+typedef struct _GtkWidget GtkWidget;
+
+namespace ui {
+class MenuModel;
+}
+
+namespace electron {
+
+namespace gtkui {
+
+class MenuGtk {
+ public:
+  explicit MenuGtk(ui::MenuModel* model);
+  virtual ~MenuGtk();
+
+  // Refreshes all the menu item labels and menu item checked/enabled states.
+  void Refresh();
+
+  GtkMenu* GetGtkMenu();
+
+ private:
+  // Callback for when a menu item is activated.
+  CHROMEG_CALLBACK_0(MenuGtk, void, OnMenuItemActivated, GtkWidget*);
+
+  raw_ptr<ui::MenuModel> menu_model_;  // not owned
+  ScopedGObject<GtkWidget> gtk_menu_;
+
+  bool block_activation_ = false;
+};
+
+}  // namespace gtkui
+
+}  // namespace electron
+
+#endif  // ELECTRON_SHELL_BROWSER_UI_GTK_MENU_GTK_H_