VariableChooser: Add support for (plain) text edits

Task-number: QTCREATORBUG-4309
Change-Id: I3d81244fe380bdf79e108f41c2c06df88b116137
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

src/plugins/coreplugin/variablechooser.h

@@ -71,6 +71,7 @@ private slots:
     void updatePositionAndShow();
 
 private:
+    QWidget *currentWidget();
     void createIconButton();
 
     Internal::Ui::VariableChooser *ui;