The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/59a2ae4c4d36be31e18d4c91165aff29a7568cc9

commit 59a2ae4c4d36be31e18d4c91165aff29a7568cc9
Author: Harald Alvestrand <hta@chromium.org>
Date: Mon Jan 22 13:12:47 2018

Add tests to verify behavior of the DtlsSrtpKeyAgreement constraint

The DtlsSrtpKeyAgreement constraint, when explicit false, sets
the deprecated SDES key negotiation mode.
This test verifies that:

- SDES mode can talk to SDES mode
- SDES mode can NOT talk to (normal) DTLS mode
- The only legitimate syntaxes for the constraint are "old style"

This helps limit the number of patterns we have to look for
when evaluating whether the deprecation of the feature is working.

Bug: 804275
Change-Id: I0ea05af6eb4cb2ffd1f7d2fd8b48d64af49cb63e
Reviewed-on: https://chromium-review.googlesource.com/877891
Commit-Queue: Harald Alvestrand <hta@chromium.org>
Reviewed-by: Henrik Boström <hbos@chromium.org>
Cr-Commit-Position: refs/heads/master@{#530850}
[add] https://crrev.com/59a2ae4c4d36be31e18d4c91165aff29a7568cc9/third_party/WebKit/LayoutTests/fast/peerconnection/RTCPeerConnection-sdes-constraint.html

The following revision refers to this bug:
  https://webrtc.googlesource.com/src.git/+/194939b8ca3c2c36ba7615bbd32348e44fafbce8

commit 194939b8ca3c2c36ba7615bbd32348e44fafbce8
Author: Harald Alvestrand <hta@webrtc.org>
Date: Wed Jan 24 16:09:59 2018

Added UMA counters for SDES vs DTLS key agreement

This is required to figure out when we can deprecate and remove
SDES.

Bug: chromium:804275
Change-Id: Ie234e6b3c8f5de8e78dda8d755d955caa61b7aa7
Reviewed-on: https://webrtc-review.googlesource.com/43340
Reviewed-by: Fredrik Solenberg <solenberg@webrtc.org>
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21746}
[modify] https://crrev.com/194939b8ca3c2c36ba7615bbd32348e44fafbce8/api/umametrics.h
[modify] https://crrev.com/194939b8ca3c2c36ba7615bbd32348e44fafbce8/pc/peerconnection.cc
[modify] https://crrev.com/194939b8ca3c2c36ba7615bbd32348e44fafbce8/pc/peerconnection_integrationtest.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/914c00e52f9383b4312eecc9f6624128e0d73920

commit 914c00e52f9383b4312eecc9f6624128e0d73920
Author: Harald Alvestrand <hta@chromium.org>
Date: Tue Jan 30 12:15:06 2018

Expose WebRTC counter for key protocol to UMA

This allows to observe how many WebRTC users use the deprecated
SDES key agreement style and how many use the DTLS style.

Bug: 804275
Change-Id: I0220328a0897e67fde387288ad6ec1475dca3de3
Reviewed-on: https://chromium-review.googlesource.com/891224
Commit-Queue: Henrik Boström <hbos@chromium.org>
Reviewed-by: Henrik Boström <hbos@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532847}
[modify] https://crrev.com/914c00e52f9383b4312eecc9f6624128e0d73920/content/renderer/media/rtc_peer_connection_handler.cc
[modify] https://crrev.com/914c00e52f9383b4312eecc9f6624128e0d73920/tools/metrics/histograms/enums.xml
[modify] https://crrev.com/914c00e52f9383b4312eecc9f6624128e0d73920/tools/metrics/histograms/histograms.xml

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/899988fb61f1cf591b933d71d27e938303eeed1e

commit 899988fb61f1cf591b933d71d27e938303eeed1e
Author: Harald Alvestrand <hta@chromium.org>
Date: Thu Mar 01 20:12:38 2018

Add use counters for EnableDtlsSrtp constraint

These will be turned into deprecation warnings when we
start deprecating SDES crypto and the constraint.

Bug: 804275
Change-Id: I0c5763406b9f4bd32890708e34a132ad6553a929
Reviewed-on: https://chromium-review.googlesource.com/941955
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Henrik Boström <hbos@chromium.org>
Commit-Queue: Harald Alvestrand <hta@chromium.org>
Cr-Commit-Position: refs/heads/master@{#540265}
[modify] https://crrev.com/899988fb61f1cf591b933d71d27e938303eeed1e/third_party/WebKit/Source/modules/mediastream/MediaConstraintsImpl.cpp
[modify] https://crrev.com/899988fb61f1cf591b933d71d27e938303eeed1e/third_party/WebKit/public/platform/web_feature.mojom
[modify] https://crrev.com/899988fb61f1cf591b933d71d27e938303eeed1e/tools/metrics/histograms/enums.xml

Comment from @juberti: Would like more data showing percentages for specific media types - whether we have SDES on a significant percentage of audio/video.

ideally you would also correlate it with the hideous RTP data channels and the RAPPPOR stuff.

The following revision refers to this bug:
  https://webrtc.googlesource.com/src.git/+/f9d0f1d215e627fb187721ce666becda2d16aceb

commit f9d0f1d215e627fb187721ce666becda2d16aceb
Author: Harald Alvestrand <hta@webrtc.org>
Date: Mon Mar 05 13:46:43 2018

UMA counters for SDES x media type

These counters will register whether the media sections
used with SDES are for audio, video or data.

Bug: chromium:804275
Change-Id: I1da3bb6625af755c0897bf4cd349655cb283fbb6
Reviewed-on: https://webrtc-review.googlesource.com/59400
Reviewed-by: Fredrik Solenberg <solenberg@webrtc.org>
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22287}
[modify] https://crrev.com/f9d0f1d215e627fb187721ce666becda2d16aceb/api/umametrics.h
[modify] https://crrev.com/f9d0f1d215e627fb187721ce666becda2d16aceb/pc/peerconnection.cc

Note: On wiring up this into Chrome, I discovered that we're only counting the first media section in each bundle group. This may skew the results.

The following revision refers to this bug:
  https://webrtc.googlesource.com/src.git/+/2e18061033d36923b2377cbb31dd64e4494f49d2

commit 2e18061033d36923b2377cbb31dd64e4494f49d2
Author: Harald Alvestrand <hta@webrtc.org>
Date: Wed Mar 07 11:32:55 2018

Count key protocol for all media sections

This will give accurate stats for the number of calls
that use video that are using SDES.

Bug: chromium:804275
Change-Id: I35b045a2301fb5267b656b424b9b3482b1b72f9a
Reviewed-on: https://webrtc-review.googlesource.com/60481
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22324}
[modify] https://crrev.com/2e18061033d36923b2377cbb31dd64e4494f49d2/pc/peerconnection.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/29a25683789611e2b345bccff42746764500ebda

commit 29a25683789611e2b345bccff42746764500ebda
Author: Harald Alvestrand <hta@chromium.org>
Date: Thu Mar 08 09:54:20 2018

Wire up UMA for key exchange protocol by media type

Bug: chromium:804275
Change-Id: Id76cce71074ddde14b7e5179d1e536d0658154a1
Reviewed-on: https://chromium-review.googlesource.com/951785
Commit-Queue: Harald Alvestrand <hta@chromium.org>
Reviewed-by: Henrik Boström <hbos@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541761}
[modify] https://crrev.com/29a25683789611e2b345bccff42746764500ebda/content/renderer/media/webrtc/rtc_peer_connection_handler.cc
[modify] https://crrev.com/29a25683789611e2b345bccff42746764500ebda/tools/metrics/histograms/enums.xml
[modify] https://crrev.com/29a25683789611e2b345bccff42746764500ebda/tools/metrics/histograms/histograms.xml