The value of AudioFrame::energy_ must be set to -1 in order to have the energy calculated later on in the AudioConferenceMixer module. This was not the case in ACM2, where the value was set to 0 instead. This resulted in bad audio for multi-party calls (5 or more participants). Implemented a unit test to verify ACM output frame. BUG=3255 TBR=turaj@webrtc.org Review URL: https://webrtc-codereview.appspot.com/12369005 git-svn-id: http://webrtc.googlecode.com/svn/trunk@5969 4adac7df-926f-26a2-2b94-8c16560cd09d