begin libadwaita headerbar tabs integration

src/app/browser/window/header/bar/control/widget.rs

@@ -0,0 +1,20 @@
+use gtk::{PackType, WindowControls};
+use std::sync::Arc;
+
+pub struct Widget {
+    gobject: WindowControls,
+}
+
+impl Widget {
+    // Construct
+    pub fn new_arc() -> Arc<Self> {
+        Arc::new(Self {
+            gobject: WindowControls::new(PackType::End),
+        })
+    }
+
+    // Getters
+    pub fn gobject(&self) -> &WindowControls {
+        &self.gobject
+    }
+}