c28a896a7b
BUG=4690 Changes: 1. In MediaEngineInterface changed CreateChannel() to CreateChannel(const AudioOptions&). Plan is to eventually remove Get/SetAudioOptions and the cousins SetDelayOffset and SetDevices. 2. In ChannelManager changed CreateVoiceChannel(...) to CreateVoiceChannel(..., const AudioOptions&). 3. In ChannelManager removed SetEngineAudioOptions, because it is not used and we want to eventually remove SetAudioOptions. 4. Updated MediaEngineInterface implementations and unit tests accordingly. 5. In WebRtcVoiceEngine changed access of Set/ClearOptionOverrides to protected. These are only used by WebRtcVoiceMediaChannel (now a friend). Plan is to rethink the logic behind option overrides. 6. Cosmetics: replaced NULL with nullptr in touched code R=solenberg@google.com, tommi@webrtc.org Review URL: https://webrtc-codereview.appspot.com/56499004 Cr-Commit-Position: refs/heads/master@{#9330}