use modern (2018) pattern for modules

src/browser/header.rs

@@ -0,0 +1,36 @@
+mod subject;
+mod tray;
+
+use subject::Subject;
+use tray::Tray;
+
+use gtk::{glib::GString, HeaderBar};
+
+pub struct Header {
+    widget: HeaderBar,
+    subject: Subject,
+}
+
+impl Header {
+    // Construct
+    pub fn new() -> Self {
+        let tray = Tray::new();
+        let subject = Subject::new();
+
+        let widget = HeaderBar::builder().build();
+        widget.pack_start(tray.widget());
+        widget.set_title_widget(Some(subject.widget()));
+
+        Self { widget, subject }
+    }
+
+    // Actions
+    pub fn update(&self, title: Option<GString>, description: Option<GString>) {
+        self.subject.update(title, description);
+    }
+
+    // Getters
+    pub fn widget(&self) -> &HeaderBar {
+        &self.widget
+    }
+}