Google and Yahoo plugins to use it.
bug=340857
r=gavin
sr/branch=mconnor
git-svn-id: svn://10.0.0.236/trunk@200145 18797224-902f-48f8-a5cc-f745e15eee43
and provides an increasing backoff behavior if the server returns an HTTP
response code that indicates that it's too busy.
bug=339441
r=gavin
sr/branch=mconnor
git-svn-id: svn://10.0.0.236/trunk@200043 18797224-902f-48f8-a5cc-f745e15eee43