Two problems fixed in this CL: - setting Opus decoder to stereo had no effect, and decoding always generated mono audio - changing decoding setting from mono to stereo, or stereo to mono, for OPUS also had no effect (but required another change than the first one). BUG=3082 R=henrik.lundin@webrtc.org, turaj@webrtc.org Review URL: https://webrtc-codereview.appspot.com/10389004 git-svn-id: http://webrtc.googlecode.com/svn/trunk@5754 4adac7df-926f-26a2-2b94-8c16560cd09d