\brief plugin size policy default plugin size policy

\brief position get current dock position \return

\brief positionChanged override this function to receive dock position changed signal \param position

\brief refreshIcon refresh item icon, its triggered when system icon theme changed. \param itemKey item key

\brief setItemIsInContainer save your item new state. this function called when user drag out your item from container or user drop item into containe

* @brief 将插件的参数(Order, Visible, etc)写入gsettings * 自动化测试需要通过dbus(GetPluginSettings)获取这些参数 */