ClipboardHistory: Add a Clear history action

This clears the history from the table view and clears the clipboard.

Userland/Applets/ClipboardHistory/ClipboardHistoryModel.cpp

@@ -136,6 +136,12 @@ void ClipboardHistoryModel::remove_item(int index)
     invalidate();
 }
 
+void ClipboardHistoryModel::clear()
+{
+    m_history_items.clear();
+    invalidate();
+}
+
 void ClipboardHistoryModel::config_string_did_change(DeprecatedString const& domain, DeprecatedString const& group, DeprecatedString const& key, DeprecatedString const& value_string)
 {
     if (domain != "ClipboardHistory" || group != "ClipboardHistory")

Userland/Applets/ClipboardHistory/ClipboardHistoryModel.h

@@ -38,6 +38,7 @@ public:
     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);
+    void clear();
     bool is_empty() { return m_history_items.is_empty(); }
 
     // ^GUI::Model

Userland/Applets/ClipboardHistory/main.cpp

@@ -67,12 +67,20 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
         });
     });
 
+    auto clear_action = GUI::Action::create("Clear history", TRY(Gfx::Bitmap::try_load_from_file("/res/icons/16x16/trash-can.png"sv)), [&](const GUI::Action&) {
+        model->clear();
+        GUI::Clipboard::the().clear();
+    });
+
     auto entry_context_menu = TRY(GUI::Menu::try_create());
     TRY(entry_context_menu->try_add_action(delete_action));
     TRY(entry_context_menu->try_add_action(debug_dump_action));
+    entry_context_menu->add_separator();
+    TRY(entry_context_menu->try_add_action(clear_action));
     table_view->on_context_menu_request = [&](GUI::ModelIndex const&, GUI::ContextMenuEvent const& event) {
         delete_action->set_enabled(!table_view->selection().is_empty());
         debug_dump_action->set_enabled(!table_view->selection().is_empty());
+        clear_action->set_enabled(!model->is_empty());
         entry_context_menu->popup(event.screen_position());
     };