Revert of Refactoring that removes P2PTransport and DtlsTransport classes.

Revert of Refactoring that removes P2PTransport and DtlsTransport classes. (patchset #9 id:150001 of https://codereview.webrtc.org/2517883002/ )

Reason for revert:
Deletion of transport.h broke downstream builds.

Going to reland with transport.h containing enums/etc.

Original issue's description:
> Refactoring that removes P2PTransport and DtlsTransport classes.
>
> Their base class, Transport, still exists, but it now has a more specific
> role: a helper class that applies TransportDescriptions. And is renamed
> to JsepTransport as a result.
>
> TransportController is now the entity primarily responsible for managing
> TransportChannels. It also starts storing pointers to the DTLS and ICE
> chanels separately, which will make it easier to remove
> TransportChannel/TransportChannelImpl in a subsequent CL.
>
> BUG=None
>
> Committed: https://crrev.com/bd28681d02dee8c185aeb39207e8154f0ad14a37
> Cr-Commit-Position: refs/heads/master@{#15450}

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

Committed: https://crrev.com/57fd7263d1d5bfe27e7c540b5251485da6a7c30e
Cr-Commit-Position: refs/heads/master@{#15452}

[Taylor Brandstetter, 2016-12-06 23:28:38]

The CQ bit was checked by deadbeef@webrtc.org

[Taylor Brandstetter, 2016-12-06 23:28:38]

Created Revert of Refactoring that removes P2PTransport and DtlsTransport
classes.

[commit-bot: I haz the power, 2016-12-06 23:28:47]

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, 2016-12-06 23:28:59]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1481066918423320, "parent_rev":
"6f6e8b52b7e605412d054d080b3e0cb7d01dad1e", "commit_rev":
"fdc0bee1c6f964f31436da79d4d5434a80fe33c8"}

[commit-bot: I haz the power, 2016-12-06 23:29:02]

Description was changed from

==========
Revert of Refactoring that removes P2PTransport and DtlsTransport classes.
(patchset #9 id:150001 of https://codereview.webrtc.org/2517883002/ )

Reason for revert:
Deletion of transport.h broke downstream builds.

Going to reland with transport.h containing enums/etc.

Original issue's description:
> Refactoring that removes P2PTransport and DtlsTransport classes.
> 
> Their base class, Transport, still exists, but it now has a more specific
> role: a helper class that applies TransportDescriptions. And is renamed
> to JsepTransport as a result.
> 
> TransportController is now the entity primarily responsible for managing
> TransportChannels. It also starts storing pointers to the DTLS and ICE
> chanels separately, which will make it easier to remove
> TransportChannel/TransportChannelImpl in a subsequent CL.
> 
> BUG=None
> 
> Committed: https://crrev.com/bd28681d02dee8c185aeb39207e8154f0ad14a37
> Cr-Commit-Position: refs/heads/master@{#15450}

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 Refactoring that removes P2PTransport and DtlsTransport classes.
(patchset #9 id:150001 of https://codereview.webrtc.org/2517883002/ )

Reason for revert:
Deletion of transport.h broke downstream builds.

Going to reland with transport.h containing enums/etc.

Original issue's description:
> Refactoring that removes P2PTransport and DtlsTransport classes.
> 
> Their base class, Transport, still exists, but it now has a more specific
> role: a helper class that applies TransportDescriptions. And is renamed
> to JsepTransport as a result.
> 
> TransportController is now the entity primarily responsible for managing
> TransportChannels. It also starts storing pointers to the DTLS and ICE
> chanels separately, which will make it easier to remove
> TransportChannel/TransportChannelImpl in a subsequent CL.
> 
> BUG=None
> 
> Committed: https://crrev.com/bd28681d02dee8c185aeb39207e8154f0ad14a37
> Cr-Commit-Position: refs/heads/master@{#15450}

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

[commit-bot: I haz the power, 2016-12-06 23:29:03]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-12-06 23:29:12]

Description was changed from

==========
Revert of Refactoring that removes P2PTransport and DtlsTransport classes.
(patchset #9 id:150001 of https://codereview.webrtc.org/2517883002/ )

Reason for revert:
Deletion of transport.h broke downstream builds.

Going to reland with transport.h containing enums/etc.

Original issue's description:
> Refactoring that removes P2PTransport and DtlsTransport classes.
> 
> Their base class, Transport, still exists, but it now has a more specific
> role: a helper class that applies TransportDescriptions. And is renamed
> to JsepTransport as a result.
> 
> TransportController is now the entity primarily responsible for managing
> TransportChannels. It also starts storing pointers to the DTLS and ICE
> chanels separately, which will make it easier to remove
> TransportChannel/TransportChannelImpl in a subsequent CL.
> 
> BUG=None
> 
> Committed: https://crrev.com/bd28681d02dee8c185aeb39207e8154f0ad14a37
> Cr-Commit-Position: refs/heads/master@{#15450}

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 Refactoring that removes P2PTransport and DtlsTransport classes.
(patchset #9 id:150001 of https://codereview.webrtc.org/2517883002/ )

Reason for revert:
Deletion of transport.h broke downstream builds.

Going to reland with transport.h containing enums/etc.

Original issue's description:
> Refactoring that removes P2PTransport and DtlsTransport classes.
>
> Their base class, Transport, still exists, but it now has a more specific
> role: a helper class that applies TransportDescriptions. And is renamed
> to JsepTransport as a result.
>
> TransportController is now the entity primarily responsible for managing
> TransportChannels. It also starts storing pointers to the DTLS and ICE
> chanels separately, which will make it easier to remove
> TransportChannel/TransportChannelImpl in a subsequent CL.
>
> BUG=None
>
> Committed: https://crrev.com/bd28681d02dee8c185aeb39207e8154f0ad14a37
> Cr-Commit-Position: refs/heads/master@{#15450}

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

Committed: https://crrev.com/57fd7263d1d5bfe27e7c540b5251485da6a7c30e
Cr-Commit-Position: refs/heads/master@{#15452}
==========

[commit-bot: I haz the power, 2016-12-06 23:29:13]

Patchset 1 (id:??) landed as
https://crrev.com/57fd7263d1d5bfe27e7c540b5251485da6a7c30e
Cr-Commit-Position: refs/heads/master@{#15452}