Reland of Add content type information to encoded images and corresponding rtp extension header

Reland of Add content type information to encoded images and corresponding rtp extension header (patchset #1 id:1 of https://codereview.webrtc.org/2816463002/ )

Reason for revert:
Reland with fixes which break API

Original issue's description:
> Revert of Add content type information to encoded images and corresponding rtp extension header (patchset #31 id:600001 of https://codereview.webrtc.org/2772033002/ )
> 
> Reason for revert:
> Breaks dependent projects.
> 
> Original issue's description:
> > Add content type information to Encoded Images and add corresponding RTP extension header.
> > Use it to separate UMA e2e delay metric between screenshare from video.
> > Content type extension is set based on encoder settings and processed and decoders.
> > 
> > Also,
> > Fix full-stack-tests to calculate RTT correctly, so new metric could be tested.
> > 
> > BUG=webrtc:7420
> > 
> > Review-Url: https://codereview.webrtc.org/2772033002
> > Cr-Commit-Position: refs/heads/master@{#17640}
> > Committed: https://chromium.googlesource.com/external/webrtc/+/64e739aeae5629cbbebf2a19e1d3e6b452bb6d0b
> 
> TBR=tommi@webrtc.org,sprang@webrtc.org,stefan@webrtc.org,nisse@webrtc.org,mflodman@webrtc.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=webrtc:7420
> 
> Review-Url: https://codereview.webrtc.org/2816463002
> Cr-Commit-Position: refs/heads/master@{#17644}
> Committed: https://chromium.googlesource.com/external/webrtc/+/57218668083fce36a55efb8c8f1d31785253b8c0

TBR=tommi@webrtc.org,sprang@webrtc.org,stefan@webrtc.org,nisse@webrtc.org,mflodman@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:7420
Review-Url: https://codereview.webrtc.org/2811963002
Cr-Commit-Position: refs/heads/master@{#17645}
Committed: https://chromium.googlesource.com/external/webrtc/+/4fa0c4f97fec5fd7d52ed505ae1d086ded6ceb9a

[ilnik, 2017-04-11 11:01:21]

The CQ bit was checked by ilnik@webrtc.org

[ilnik, 2017-04-11 11:01:21]

Created Reland of Add content type information to encoded images and
corresponding rtp extension header

[commit-bot: I haz the power, 2017-04-11 11:01:33]

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, 2017-04-11 11:01:44]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1491908481025720, "parent_rev":
"57218668083fce36a55efb8c8f1d31785253b8c0", "commit_rev":
"4fa0c4f97fec5fd7d52ed505ae1d086ded6ceb9a"}

[commit-bot: I haz the power, 2017-04-11 11:01:47]

Description was changed from

==========
Reland of Add content type information to encoded images and corresponding rtp
extension header (patchset #1 id:1 of https://codereview.webrtc.org/2816463002/
)

Reason for revert:
Reland with fixes which break API

Original issue's description:
> Revert of Add content type information to encoded images and corresponding rtp
extension header (patchset #31 id:600001 of
https://codereview.webrtc.org/2772033002/ )
> 
> Reason for revert:
> Breaks dependent projects.
> 
> Original issue's description:
> > Add content type information to Encoded Images and add corresponding RTP
extension header.
> > Use it to separate UMA e2e delay metric between screenshare from video.
> > Content type extension is set based on encoder settings and processed and
decoders.
> > 
> > Also,
> > Fix full-stack-tests to calculate RTT correctly, so new metric could be
tested.
> > 
> > BUG=webrtc:7420
> > 
> > Review-Url: https://codereview.webrtc.org/2772033002
> > Cr-Commit-Position: refs/heads/master@{#17640}
> > Committed:
https://chromium.googlesource.com/external/webrtc/+/64e739aeae5629cbbebf2a19e...
> 
>
TBR=tommi@webrtc.org,sprang@webrtc.org,stefan@webrtc.org,nisse@webrtc.org,mfl...
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=webrtc:7420
> 
> Review-Url: https://codereview.webrtc.org/2816463002
> Cr-Commit-Position: refs/heads/master@{#17644}
> Committed:
https://chromium.googlesource.com/external/webrtc/+/57218668083fce36a55efb8c8...

TBR=tommi@webrtc.org,sprang@webrtc.org,stefan@webrtc.org,nisse@webrtc.org,mfl...
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:7420
==========

to

==========
Reland of Add content type information to encoded images and corresponding rtp
extension header (patchset #1 id:1 of https://codereview.webrtc.org/2816463002/
)

Reason for revert:
Reland with fixes which break API

Original issue's description:
> Revert of Add content type information to encoded images and corresponding rtp
extension header (patchset #31 id:600001 of
https://codereview.webrtc.org/2772033002/ )
> 
> Reason for revert:
> Breaks dependent projects.
> 
> Original issue's description:
> > Add content type information to Encoded Images and add corresponding RTP
extension header.
> > Use it to separate UMA e2e delay metric between screenshare from video.
> > Content type extension is set based on encoder settings and processed and
decoders.
> > 
> > Also,
> > Fix full-stack-tests to calculate RTT correctly, so new metric could be
tested.
> > 
> > BUG=webrtc:7420
> > 
> > Review-Url: https://codereview.webrtc.org/2772033002
> > Cr-Commit-Position: refs/heads/master@{#17640}
> > Committed:
https://chromium.googlesource.com/external/webrtc/+/64e739aeae5629cbbebf2a19e...
> 
>
TBR=tommi@webrtc.org,sprang@webrtc.org,stefan@webrtc.org,nisse@webrtc.org,mfl...
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=webrtc:7420
> 
> Review-Url: https://codereview.webrtc.org/2816463002
> Cr-Commit-Position: refs/heads/master@{#17644}
> Committed:
https://chromium.googlesource.com/external/webrtc/+/57218668083fce36a55efb8c8...

TBR=tommi@webrtc.org,sprang@webrtc.org,stefan@webrtc.org,nisse@webrtc.org,mfl...
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:7420

Review-Url: https://codereview.webrtc.org/2811963002
Cr-Commit-Position: refs/heads/master@{#17645}
Committed:
https://chromium.googlesource.com/external/webrtc/+/4fa0c4f97fec5fd7d52ed505a...
==========

[commit-bot: I haz the power, 2017-04-11 11:01:48]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/external/webrtc/+/4fa0c4f97fec5fd7d52ed505a...

[ilnik, 2017-04-11 11:19:19]

A revert of this CL (patchset #2 id:300001) has been created in
https://codereview.webrtc.org/2806263006/ by ilnik@webrtc.org.

The reason for reverting is: Relanded prematurely by mistake..

[ilnik, 2017-04-11 11:48:09]

Patchset #2 (id:300001) has been deleted

[ilnik, 2017-04-11 11:48:45]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.webrtc.org/2810923004/ by ilnik@webrtc.org.

The reason for reverting is: Relanded by mistake..