Revert of Separating SCTP code from BaseChannel/MediaChannel.

Revert of Separating SCTP code from BaseChannel/MediaChannel. (patchset #14 id:240001 of https://codereview.webrtc.org/2564333002/ )

Reason for revert:
Hitting DCHECK in chromium's WebrtcTransportTest.TerminateDataChannel and WebrtcTransportTest.DataStreamLate. Will investigate and reland.

Original issue's description:
> Separating SCTP code from BaseChannel/MediaChannel.
> 
> The BaseChannel code is geared around RTP; the presence of media engines,
> send and receive streams, SRTP, SDP directional attribute negotiation, etc.
> It doesn't make sense to use it for SCTP as well. This separation should make
> future work both on BaseChannel and the SCTP code paths easier.
> 
> SctpDataEngine now becomes SctpTransport, and is used by WebRtcSession
> directly. cricket::DataChannel is also renamed, to RtpDataChannel, so it
> doesn't get confused with webrtc::DataChannel any more.
> 
> Beyond just moving code around, some consequences of this CL:
> - We'll now stop using the worker thread for SCTP. Packets will be
>   processed right on the network thread instead.
> - The SDP directional attribute is ignored, as it's supposed to be.
> 
> BUG=None
> 
> Review-Url: https://codereview.webrtc.org/2564333002
> Cr-Commit-Position: refs/heads/master@{#15906}
> Committed: https://chromium.googlesource.com/external/webrtc/+/67b3bbe639645ab719972682359acda303d94454

TBR=pthatcher@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=None

Review-Url: https://codereview.webrtc.org/2614813003
Cr-Commit-Position: refs/heads/master@{#15908}
Committed: https://chromium.googlesource.com/external/webrtc/+/c0dad89bed44c05a8a4c01f6c7a0fd58912479aa

[Taylor Brandstetter, 2017-01-05 04:24:29]

Created Revert of Separating SCTP code from BaseChannel/MediaChannel.

[Taylor Brandstetter, 2017-01-05 04:28:03]

The CQ bit was checked by deadbeef@webrtc.org

[commit-bot: I haz the power, 2017-01-05 04:28:11]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.webrtc.org/...

[commit-bot: I haz the power, 2017-01-05 04:28:21]

CQ is committing da patch.

Bot data: {"patchset_id": 270001, "attempt_start_ts": 1483590483629890,
"parent_rev": "e9bbde583043051e9c55f30b938efc29db28b962", "commit_rev":
"c0dad89bed44c05a8a4c01f6c7a0fd58912479aa"}

[commit-bot: I haz the power, 2017-01-05 04:28:24]

Description was changed from

==========
Revert of Separating SCTP code from BaseChannel/MediaChannel. (patchset #14
id:240001 of https://codereview.webrtc.org/2564333002/ )

Reason for revert:
Hitting DCHECK in chromium's WebrtcTransportTest.TerminateDataChannel and
WebrtcTransportTest.DataStreamLate. Will investigate and reland.

Original issue's description:
> Separating SCTP code from BaseChannel/MediaChannel.
> 
> The BaseChannel code is geared around RTP; the presence of media engines,
> send and receive streams, SRTP, SDP directional attribute negotiation, etc.
> It doesn't make sense to use it for SCTP as well. This separation should make
> future work both on BaseChannel and the SCTP code paths easier.
> 
> SctpDataEngine now becomes SctpTransport, and is used by WebRtcSession
> directly. cricket::DataChannel is also renamed, to RtpDataChannel, so it
> doesn't get confused with webrtc::DataChannel any more.
> 
> Beyond just moving code around, some consequences of this CL:
> - We'll now stop using the worker thread for SCTP. Packets will be
>   processed right on the network thread instead.
> - The SDP directional attribute is ignored, as it's supposed to be.
> 
> BUG=None
> 
> Review-Url: https://codereview.webrtc.org/2564333002
> Cr-Commit-Position: refs/heads/master@{#15906}
> Committed:
https://chromium.googlesource.com/external/webrtc/+/67b3bbe639645ab7199726823...

TBR=pthatcher@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=None
==========

to

==========
Revert of Separating SCTP code from BaseChannel/MediaChannel. (patchset #14
id:240001 of https://codereview.webrtc.org/2564333002/ )

Reason for revert:
Hitting DCHECK in chromium's WebrtcTransportTest.TerminateDataChannel and
WebrtcTransportTest.DataStreamLate. Will investigate and reland.

Original issue's description:
> Separating SCTP code from BaseChannel/MediaChannel.
> 
> The BaseChannel code is geared around RTP; the presence of media engines,
> send and receive streams, SRTP, SDP directional attribute negotiation, etc.
> It doesn't make sense to use it for SCTP as well. This separation should make
> future work both on BaseChannel and the SCTP code paths easier.
> 
> SctpDataEngine now becomes SctpTransport, and is used by WebRtcSession
> directly. cricket::DataChannel is also renamed, to RtpDataChannel, so it
> doesn't get confused with webrtc::DataChannel any more.
> 
> Beyond just moving code around, some consequences of this CL:
> - We'll now stop using the worker thread for SCTP. Packets will be
>   processed right on the network thread instead.
> - The SDP directional attribute is ignored, as it's supposed to be.
> 
> BUG=None
> 
> Review-Url: https://codereview.webrtc.org/2564333002
> Cr-Commit-Position: refs/heads/master@{#15906}
> Committed:
https://chromium.googlesource.com/external/webrtc/+/67b3bbe639645ab7199726823...

TBR=pthatcher@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=None

Review-Url: https://codereview.webrtc.org/2614813003
Cr-Commit-Position: refs/heads/master@{#15908}
Committed:
https://chromium.googlesource.com/external/webrtc/+/c0dad89bed44c05a8a4c01f6c...
==========

[commit-bot: I haz the power, 2017-01-05 04:28:24]

Committed patchset #2 (id:270001) as
https://chromium.googlesource.com/external/webrtc/+/c0dad89bed44c05a8a4c01f6c...