api (still not ui) to add panel spacer

src/shell/panelconfigview.cpp

@@ -87,6 +87,11 @@ void PanelConfigView::showAddWidgetDialog()
     }
 }
 
+void PanelConfigView::addPanelSpacer()
+{
+    m_containment->createApplet("org.kde.plasma.panelspacer");
+}
+
 void PanelConfigView::syncGeometry()
 {
     if (!m_containment || !rootObject()) {

src/shell/panelconfigview.h

@@ -49,6 +49,7 @@ public:
 
 public Q_SLOTS:
     void showAddWidgetDialog();
+    void addPanelSpacer();
 
 protected:
     void focusOutEvent(QFocusEvent *ev);