LibGUI: Don't require passing a parent to widget constructors

This is a step towards using Core::Object::add<T> more, which takes
care of parenting the newly created child automatically.

1 files changed, 2 insertions, 2 deletions

diff --git a/Libraries/LibGUI/Slider.h b/Libraries/LibGUI/Slider.h
index 5b26cc6161..60e5a0cc27 100644
--- a/Libraries/LibGUI/Slider.h
+++ b/Libraries/LibGUI/Slider.h
@@ -106,7 +106,7 @@ public:
     virtual ~VerticalSlider() override {}
 
 private:
-    explicit VerticalSlider(Widget* parent)
+    explicit VerticalSlider(Widget* parent = nullptr)
         : Slider(Orientation::Vertical, parent)
     {
     }
@@ -118,7 +118,7 @@ public:
     virtual ~HorizontalSlider() override {}
 
 private:
-    explicit HorizontalSlider(Widget* parent)
+    explicit HorizontalSlider(Widget* parent = nullptr)
         : Slider(Orientation::Horizontal, parent)
     {
     }