Reland of Simplify and extend RtpHeaderExtensionMap

Reland of Simplify and extend RtpHeaderExtensionMap (patchset #1 id:1 of https://codereview.webrtc.org/2484863007/ )

Reason for revert:
dependent project adjusted

Original issue's description:
> Revert of Simplify and extend RtpHeaderExtensionMap (patchset #12 id:260001 of https://codereview.webrtc.org/2452293004/ )
>
> Reason for revert:
> breaks downstream project
>
> Original issue's description:
> > Simplify and extend RtpHeaderExtensionMap
> > Add register functions for various codepaths.
> > Add initialize-list constructor to create usable const RtpHeaderExtensionMap
> > Optimize implementation for GetId/GetType.
> >
> > BUG=webrtc:1994
> >
> > Committed: https://crrev.com/d1d26fbeb37a69471a34004c6ac2d3fafde5d404
> > Cr-Commit-Position: refs/heads/master@{#14986}
>
> TBR=sprang@webrtc.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=webrtc:1994
>
> Committed: https://crrev.com/bc38b4d450a80bf45efbe5b0a452e0374cdae1e6
> Cr-Commit-Position: refs/heads/master@{#14988}

TBR=sprang@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:1994
Committed: https://crrev.com/6ba58d67ceb34882ffa6d731c9b29f4effb68f5d
Cr-Commit-Position: refs/heads/master@{#15000}

[danilchap, 2016-11-09 12:47:46]

Created Reland of Simplify and extend RtpHeaderExtensionMap

[danilchap, 2016-11-09 13:46:25]

The CQ bit was checked by danilchap@webrtc.org

[commit-bot: I haz the power, 2016-11-09 13:46:33]

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, 2016-11-09 13:46:42]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-11-09 13:46:50]

Description was changed from

==========
Reland of Simplify and extend RtpHeaderExtensionMap (patchset #1 id:1 of
https://codereview.webrtc.org/2484863007/ )

Reason for revert:
dependent project adjusted

Original issue's description:
> Revert of Simplify and extend RtpHeaderExtensionMap (patchset #12 id:260001 of
https://codereview.webrtc.org/2452293004/ )
> 
> Reason for revert:
> breaks downstream project
> 
> Original issue's description:
> > Simplify and extend RtpHeaderExtensionMap
> > Add register functions for various codepaths.
> > Add initialize-list constructor to create usable const RtpHeaderExtensionMap
> > Optimize implementation for GetId/GetType.
> >
> > BUG=webrtc:1994
> >
> > Committed: https://crrev.com/d1d26fbeb37a69471a34004c6ac2d3fafde5d404
> > Cr-Commit-Position: refs/heads/master@{#14986}
> 
> TBR=sprang@webrtc.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=webrtc:1994
> 
> Committed: https://crrev.com/bc38b4d450a80bf45efbe5b0a452e0374cdae1e6
> Cr-Commit-Position: refs/heads/master@{#14988}

TBR=sprang@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:1994
==========

to

==========
Reland of Simplify and extend RtpHeaderExtensionMap (patchset #1 id:1 of
https://codereview.webrtc.org/2484863007/ )

Reason for revert:
dependent project adjusted

Original issue's description:
> Revert of Simplify and extend RtpHeaderExtensionMap (patchset #12 id:260001 of
https://codereview.webrtc.org/2452293004/ )
>
> Reason for revert:
> breaks downstream project
>
> Original issue's description:
> > Simplify and extend RtpHeaderExtensionMap
> > Add register functions for various codepaths.
> > Add initialize-list constructor to create usable const RtpHeaderExtensionMap
> > Optimize implementation for GetId/GetType.
> >
> > BUG=webrtc:1994
> >
> > Committed: https://crrev.com/d1d26fbeb37a69471a34004c6ac2d3fafde5d404
> > Cr-Commit-Position: refs/heads/master@{#14986}
>
> TBR=sprang@webrtc.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=webrtc:1994
>
> Committed: https://crrev.com/bc38b4d450a80bf45efbe5b0a452e0374cdae1e6
> Cr-Commit-Position: refs/heads/master@{#14988}

TBR=sprang@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:1994

Committed: https://crrev.com/6ba58d67ceb34882ffa6d731c9b29f4effb68f5d
Cr-Commit-Position: refs/heads/master@{#15000}
==========

[commit-bot: I haz the power, 2016-11-09 13:46:51]

Patchset 1 (id:??) landed as
https://crrev.com/6ba58d67ceb34882ffa6d731c9b29f4effb68f5d
Cr-Commit-Position: refs/heads/master@{#15000}