code: public static Stack getPageFlowStack( HttpServletRequest request )
      {
          ServletContext servletContext = InternalUtils.getServletContext( request );
          return PageFlowStack.get( request, servletContext, true ).getLegacyStack();
      }
docs: Get the stack of nested page flows for the current user session.  Create and store an empty
  stack if none exists.
  
  @deprecated Use {@link PageFlowStack#get(HttpServletRequest, ServletContext)} instead.
  
  @param request the current HttpServletRequest
  @return a {@link PageFlowStack} of nested page flows ({@link PageFlowController}s) for the current user session.