Section 3.8 of the spec places some requirements on CDI implementations when running with Servlet. To better suit user desires for modularity these requirements are better met by moving them to the Servlet spec. Specifically,

A servlet container must provide the following built-in beans, all of which have qualifier @Default:

• a bean with bean type javax.servlet.http.HttpServletRequest, allowing injection of a reference to the HttpServletRequest
• a bean with bean type javax.servlet.http.HttpSession, allowing injection of a reference to the HttpSession,
• a bean with bean type javax.servlet.ServletContext, allowing injection of a reference to the ServletContext,
  These beans are passivation capable dependencies, as defined in Passivation capable dependencies.