Add timeouts to the http client used by session.

Hello @dpup, @ktzhu, @majelbstoat, 

Please review the following commits I made in branch 'andrew-add-timeouts'.

672e0c79c9c7ed5e42c8bfafab52dadd21abcbf4 (2014-02-14 14:35:48 -0800)
Add timeouts to the http client used by session.

R=@dpup
R=@ktzhu
R=@majelbstoat