Fixed django#19962 - Added a note about SESSION_EXPIRE_AT_BROWSER_CLOSE and browsers that persist sessions.

Thanks David Sanders.

Author: timgraham

docs/topics/http/sessions.txt

@@ -474,6 +474,16 @@ This setting is a global default and can be overwritten at a per-session level
 by explicitly calling the :meth:`~backends.base.SessionBase.set_expiry` method
 of ``request.session`` as described above in `using sessions in views`_.
 
+.. note::
+
+ Some browsers (Chrome, for example) provide settings that allow users to
+ continue browsing sessions after closing and re-opening the browser. In
+ some cases, this can interfere with the
+ :setting:`SESSION_EXPIRE_AT_BROWSER_CLOSE` setting and prevent sessions
+ from expiring on browser close. Please be aware of this while testing
+ Django applications which have the
+ :setting:`SESSION_EXPIRE_AT_BROWSER_CLOSE` setting enabled.
+
 Clearing the session store
 ==========================