use canonical module subfolder tree

src/browser/header/tray/menu/mod.rs

@@ -0,0 +1,17 @@
+use gtk::{gio, MenuButton};
+
+pub fn new() -> MenuButton {
+    let menu = MenuButton::builder().tooltip_text("Menu").build();
+
+    let model = gio::Menu::new();
+    let model_tab = gio::Menu::new();
+
+    model_tab.append(Some("Append"), Some("win.tab_append"));
+    model.append_submenu(Some("Tab"), &model_tab);
+    model.append(Some("Debug"), Some("win.debug"));
+    model.append(Some("Quit"), Some("win.quit"));
+
+    menu.set_menu_model(Some(&model));
+
+    menu
+}

src/browser/header/tray/mod.rs

@@ -0,0 +1,18 @@
+mod menu;
+mod tab;
+
+use gtk::prelude::BoxExt;
+use gtk::Box;
+
+pub fn new() -> Box {
+    let tray = Box::builder()
+        .orientation(gtk::Orientation::Horizontal)
+        .spacing(8)
+        .build();
+
+    // Compose childs
+    tray.append(&menu::new());
+    tray.append(&tab::new());
+
+    tray
+}

src/browser/header/tray/tab/mod.rs

@@ -0,0 +1,10 @@
+use gtk::Button;
+
+pub fn new() -> Button {
+    let tab = Button::builder()
+        .icon_name("tab-new-symbolic")
+        .tooltip_text("New tab")
+        .build();
+
+    return tab;
+}