Move timestamp conversion out of ACMGenericCodec. Also remove lock from ACMGenericCodec since the instance is always protected by acm_crit_sect_ in AudioCodingModuleImpl. Restructuring the code in AudioCodingModuleImpl::Encode to streamline the use of locks. R=minyue@webrtc.org Review URL: https://webrtc-codereview.appspot.com/46479004 Cr-Commit-Position: refs/heads/master@{#8773} git-svn-id: http://webrtc.googlecode.com/svn/trunk@8773 4adac7df-926f-26a2-2b94-8c16560cd09d