VisualBuilder: Add GGroupBox.

The icon currently looks better than a real GGroupBox. I have to fix that.

Applications/VisualBuilder/VBWidget.cpp

@@ -8,6 +8,7 @@
 #include <LibGUI/GProgressBar.h>
 #include <LibGUI/GCheckBox.h>
 #include <LibGUI/GScrollBar.h>
+#include <LibGUI/GGroupBox.h>
 
 static GWidget* build_gwidget(WidgetType type, GWidget* parent)
 {
@@ -16,6 +17,8 @@ static GWidget* build_gwidget(WidgetType type, GWidget* parent)
         return new GWidget(parent);
     case WidgetType::GScrollBar:
         return new GScrollBar(Orientation::Vertical, parent);
+    case WidgetType::GGroupBox:
+        return new GGroupBox("groupbox_1", parent);
     case WidgetType::GLabel: {
         auto* label = new GLabel(parent);
         label->set_text("label_1");

Applications/VisualBuilder/VBWidget.h

@@ -33,6 +33,7 @@ enum class WidgetType {
     GProgressBar,
     GCheckBox,
     GScrollBar,
+    GGroupBox,
 };
 
 class VBWidget : public Retainable<VBWidget>, public Weakable<VBWidget> {

Applications/VisualBuilder/main.cpp

@@ -116,5 +116,12 @@ GWindow* make_toolbox_window()
         if (auto* form = VBForm::current())
             form->insert_widget(WidgetType::GScrollBar);
     };
+    auto* groupbox_button = new GButton(widget);
+    groupbox_button->set_tooltip("GGroupBox");
+    groupbox_button->set_icon(GraphicsBitmap::load_from_file("/res/icons/vbwidgets/groupbox.png"));
+    groupbox_button->on_click = [] (GButton&) {
+        if (auto* form = VBForm::current())
+            form->insert_widget(WidgetType::GGroupBox);
+    };
     return window;
 }