*** Submitted as
https://code.google.com/p/goauth2/source/detail?r=f3b3146d6c91 ***
goauth2: Use content-type detection to select codec
R=adg, adg, nightlyone
CC=golang-dev
https://codereview.appspot.com/6900055
Committer: Andrew Gerrand <adg@golang.org>
https://codereview.appspot.com/6900055/
