protected void forgetIdentity(Subject subject) {
        if (WebUtils.isHttp(subject)) {
            HttpServletRequest request = WebUtils.getHttpRequest(subject);
            HttpServletResponse response = WebUtils.getHttpResponse(subject);
            forgetIdentity(request, response);
        }
    }
Removes the 'rememberMe' cookie from the associated {@link WebSubject}'s request/response pair.
<p/>
The {@code subject} instance is expected to be a {@link WebSubject} instance with an HTTP Request/Response pair.
If it is not a {@code WebSubject} or that {@code WebSubject} does not have an HTTP Request/Response pair, this
implementation does nothing.

@param subject the subject instance for which identity data should be forgotten from the underlying persistence
web/src/main/java/org/apache/shiro/web/mgt/CookieRememberMeManager.java