d3501adf17
Create the SrtpTransportInterface, a subclass of RtpTransportInterface, which allows the user to set the send and receive keys. The functionalities are implemented inside the RtpTransportAdapters on top of BaseChannel. BUG=webrtc:7013 Review-Url: https://codereview.webrtc.org/2714813004 Cr-Commit-Position: refs/heads/master@{#17023}