Libraries: Fix visibility of Object-derivative constructors

Derivatives of Core::Object should be constructed through
ClassName::construct(), to avoid handling ref-counted objects with
refcount zero. Fixing the visibility means that misuses like this are
more difficult.

Userland/Libraries/LibGUI/AbstractScrollableWidget.h

@@ -81,7 +81,7 @@ private:
     class AbstractScrollableWidgetScrollbar final : public Scrollbar {
         C_OBJECT(AbstractScrollableWidgetScrollbar);
 
-    protected:
+    private:
         explicit AbstractScrollableWidgetScrollbar(AbstractScrollableWidget& owner, Gfx::Orientation orientation)
             : Scrollbar(orientation)
             , m_owner(owner)
@@ -93,7 +93,6 @@ private:
             m_owner.handle_wheel_event(event, *this);
         }
 
-    private:
         AbstractScrollableWidget& m_owner;
     };
     friend class ScrollableWidgetScrollbar;

Userland/Libraries/LibGUI/BoxLayout.h

@@ -36,7 +36,7 @@ private:
 class VerticalBoxLayout final : public BoxLayout {
     C_OBJECT(VerticalBoxLayout);
 
-public:
+private:
     explicit VerticalBoxLayout()
         : BoxLayout(Gfx::Orientation::Vertical)
     {
@@ -47,7 +47,7 @@ public:
 class HorizontalBoxLayout final : public BoxLayout {
     C_OBJECT(HorizontalBoxLayout);
 
-public:
+private:
     explicit HorizontalBoxLayout()
         : BoxLayout(Gfx::Orientation::Horizontal)
     {

Userland/Libraries/LibGUI/Calendar.h

@@ -30,9 +30,6 @@ public:
         YearOnly
     };
 
-    Calendar(Core::DateTime date_time = Core::DateTime::now(), Mode mode = Month);
-    virtual ~Calendar() override;
-
     void set_selected_date(Core::DateTime date_time) { m_selected_date = date_time; }
     Core::DateTime selected_date() const { return m_selected_date; }
 
@@ -75,6 +72,9 @@ public:
     Function<void()> on_month_click;
 
 private:
+    Calendar(Core::DateTime date_time = Core::DateTime::now(), Mode mode = Month);
+    virtual ~Calendar() override;
+
     virtual void resize_event(GUI::ResizeEvent&) override;
     virtual void paint_event(GUI::PaintEvent&) override;
     virtual void mousemove_event(GUI::MouseEvent&) override;

Userland/Libraries/LibGUI/ColorPicker.cpp

@@ -129,11 +129,6 @@ private:
 class ColorSelectOverlay final : public Widget {
     C_OBJECT(ColorSelectOverlay)
 public:
-    ColorSelectOverlay()
-    {
-        set_override_cursor(Gfx::StandardCursor::Eyedropper);
-    }
-
     Optional<Color> exec()
     {
         m_event_loop = make<Core::EventLoop>();
@@ -156,6 +151,11 @@ public:
     Function<void(Color)> on_color_changed;
 
 private:
+    ColorSelectOverlay()
+    {
+        set_override_cursor(Gfx::StandardCursor::Eyedropper);
+    }
+
     virtual void mousedown_event(GUI::MouseEvent&) override { m_event_loop->quit(1); }
     virtual void mousemove_event(GUI::MouseEvent&) override
     {

Userland/Libraries/LibGUI/TextBox.h

@@ -14,7 +14,6 @@ namespace GUI {
 class TextBox : public TextEditor {
     C_OBJECT(TextBox)
 public:
-    TextBox();
     virtual ~TextBox() override;
 
     Function<void()> on_up_pressed;
@@ -23,6 +22,9 @@ public:
     void set_history_enabled(bool enabled) { m_history_enabled = enabled; }
     void add_current_text_to_history();
 
+protected:
+    TextBox();
+
 private:
     virtual void keydown_event(GUI::KeyEvent&) override;
 
@@ -39,20 +41,21 @@ private:
 
 class PasswordBox : public TextBox {
     C_OBJECT(PasswordBox)
-public:
+private:
     PasswordBox();
 };
 
 class UrlBox : public TextBox {
     C_OBJECT(UrlBox)
 public:
-    UrlBox();
     virtual ~UrlBox() override;
 
     void set_focus_transition(bool focus_transition) { m_focus_transition = focus_transition; }
     bool is_focus_transition() const { return m_focus_transition; }
 
 private:
+    UrlBox();
+
     virtual void mousedown_event(GUI::MouseEvent&) override;
     virtual void focusout_event(GUI::FocusEvent&) override;
 

Userland/Libraries/LibGUI/WindowManagerServerConnection.h

@@ -18,14 +18,14 @@ class WindowManagerServerConnection final
     , public WindowManagerClientEndpoint {
     C_OBJECT(WindowManagerServerConnection)
 public:
+    static WindowManagerServerConnection& the();
+
+private:
     WindowManagerServerConnection()
         : IPC::ServerConnection<WindowManagerClientEndpoint, WindowManagerServerEndpoint>(*this, "/tmp/portal/wm")
     {
     }
 
-    static WindowManagerServerConnection& the();
-
-private:
     virtual void window_removed(i32, i32, i32) override;
     virtual void window_state_changed(i32, i32, i32, i32, i32, u32, u32, bool, bool, bool, bool, i32, String const&, Gfx::IntRect const&, Optional<i32> const&) override;
     virtual void window_icon_bitmap_changed(i32, i32, i32, Gfx::ShareableBitmap const&) override;