ClipboardHistory: Ensure model is populated on startup

This ensures that, if the applet restarts, it will remain in sync with
the clipboard.

Userland/Applets/ClipboardHistory/ClipboardHistoryModel.h

@@ -36,6 +36,7 @@ public:
     virtual ~ClipboardHistoryModel() override = default;
 
     ClipboardItem const& item_at(int index) const { return m_history_items[index]; }
+    void add_item(const GUI::Clipboard::DataAndType& item);
     void remove_item(int index);
     bool is_empty() { return m_history_items.is_empty(); }
 
@@ -47,7 +48,6 @@ public:
 
 private:
     ClipboardHistoryModel();
-    void add_item(const GUI::Clipboard::DataAndType& item);
 
     // ^GUI::Model
     virtual int row_count(const GUI::ModelIndex&) const override { return m_history_items.size(); }

Userland/Applets/ClipboardHistory/main.cpp

@@ -35,6 +35,11 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
 
     auto table_view = TRY(main_window->set_main_widget<GUI::TableView>());
     auto model = ClipboardHistoryModel::create();
+
+    auto data_and_type = GUI::Clipboard::the().fetch_data_and_type();
+    if (!(data_and_type.data.is_empty() && data_and_type.mime_type.is_empty() && data_and_type.metadata.is_empty()))
+        model->add_item(data_and_type);
+
     table_view->set_model(model);
 
     table_view->on_activation = [&](GUI::ModelIndex const& index) {