If x-mt line is present (one or more), and the first line is dedicated
for the media transport that we support, pass the config down to this
media transport.
In the future we will do 3 changes:
1) Add MediaTransportFactory::IsSupported(config) to let the
implementation decide whether the current factory can support a given
setting
2) Add support for multiple x-mt lines. Right now the support is
minimal: we only look at the first line (because we only allow single
media transport factory). In the future, when RtpMediaTransport is
introduced, this may and will change.
3) Allow multiple MediaTransportFactories and add fallback to RTP if
media transport is not supported.
Current solution provides backward compatibility for the 2 above
extensions.
Bug: webrtc:9719
Change-Id: I82a469fecda57effc95d7d8191f4a9e4a01d199c
Reviewed-on: https://webrtc-review.googlesource.com/c/124800
Commit-Queue: Peter Slatala <psla@webrtc.org>
Reviewed-by: Bjorn Mellem <mellem@webrtc.org>
Reviewed-by: Steve Anton <steveanton@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26882}