tree 868077aec231944bc5396a0e8ac721f9a5f48996
parent 50f5add285ad2fa25c38a6bc51ee7f7dab792271
author zhihuang <zhihuang@webrtc.org> 1504220407 -0700
committer Commit Bot <commit-bot@chromium.org> 1504220407 +0000

Completed the functionalities of SrtpTransport.

The SrtpTransport takes the SRTP responsibilities from the BaseChannel
and SrtpFilter. SrtpTransport is now responsible for setting the crypto
keys, protecting and unprotecting the packets. SrtpTransport doesn't know
if the keys are from SDES or DTLS handshake.

BaseChannel is now only responsible setting the offer/answer for SDES
or extracting the key from DtlsTransport and configuring the
SrtpTransport.

SrtpFilter is used by BaseChannel as a helper for SDES negotiation.

BUG=webrtc:7013

Review-Url: https://codereview.webrtc.org/2997983002
Cr-Original-Commit-Position: refs/heads/master@{#19636}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: e683c6871fef24d3ff64f085d6bc0e965f17fcf7