PROXY_METHOD1(talk_base::scoped_refptr<DtmfSenderInterface>,
CreateDtmfSender, AudioTrackInterface*)
PROXY_METHOD2(bool, GetStats, StatsObserver*, MediaStreamTrackInterface*)
+ PROXY_METHOD3(bool, GetStats, StatsObserver*,
+ MediaStreamTrackInterface*,
+ StatsOutputLevel)
PROXY_METHOD2(talk_base::scoped_refptr<DataChannelInterface>,
CreateDataChannel, const std::string&, const DataChannelInit*)
PROXY_CONSTMETHOD0(const SessionDescriptionInterface*, local_description)