LibGUI+WindowServer: Add "visible" state to GUI actions

This patch adds a visibility state to GUI::Action. All actions default
to being visible. When invisible, they do not show up in toolbars on
menus (and importantly, they don't occupy any space).

This can be used to hide/show context-sensitive actions dynamically
without rebuilding menus and toolbars.

Thanks to Tim Slater for assuming that action visibility was a thing,
which gave me a reason to implement it! :^)

1 files changed, 13 insertions, 0 deletions

diff --git a/Userland/Libraries/LibGUI/Action.cpp b/Userland/Libraries/LibGUI/Action.cpp
index 678ee44915..8b50211017 100644
--- a/Userland/Libraries/LibGUI/Action.cpp
+++ b/Userland/Libraries/LibGUI/Action.cpp
@@ -228,6 +228,19 @@ void Action::set_enabled(bool enabled)
     });
 }
 
+void Action::set_visible(bool visible)
+{
+    if (m_visible == visible)
+        return;
+    m_visible = visible;
+    for_each_toolbar_button([visible](auto& button) {
+        button.set_visible(visible);
+    });
+    for_each_menu_item([visible](auto& item) {
+        item.set_visible(visible);
+    });
+}
+
 void Action::set_checked(bool checked)
 {
     if (m_checked == checked)