Enable G.722 for Chromium builds

BUG=3909
R=tina.legrand@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/24989004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@7555 4adac7df-926f-26a2-2b94-8c16560cd09d