The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8a68f8a307ee8b54b70d121130d1414c61a0d3c7

commit 8a68f8a307ee8b54b70d121130d1414c61a0d3c7
Author: Henrik Grunell <grunell@chromium.org>
Date: Tue Feb 13 10:36:53 2018

Split getUserMedia track start failure UMA stats bucket into audio and video.

The histogram WebRTC.UserMediaRequest.Result is replaced with WebRTC.UserMediaRequest.Result2.

Also:
* Add a missing histogram enum value for kill switch on in the now deprecated histogram.
* Un-deprecate MEDIA_DEVICE_INVALID_SECURITY_ORIGIN_DEPRECATED because usage of it was added after "deprecation".

Bug:  810369 
Change-Id: Ic527f96a709c121ed4108e98a5336a633ebbe797
Reviewed-on: https://chromium-review.googlesource.com/908452
Commit-Queue: Henrik Grunell <grunell@chromium.org>
Reviewed-by: Greg Kerr <kerrnel@chromium.org>
Reviewed-by: Antoine Labour <piman@chromium.org>
Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Reviewed-by: Mark Pearson <mpearson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#536326}
[modify] https://crrev.com/8a68f8a307ee8b54b70d121130d1414c61a0d3c7/content/browser/renderer_host/media/media_stream_dispatcher_host.cc
[modify] https://crrev.com/8a68f8a307ee8b54b70d121130d1414c61a0d3c7/content/common/media/media_stream.mojom
[modify] https://crrev.com/8a68f8a307ee8b54b70d121130d1414c61a0d3c7/content/common/media/media_stream_typemap_traits.cc
[modify] https://crrev.com/8a68f8a307ee8b54b70d121130d1414c61a0d3c7/content/public/common/media_stream_request.h
[modify] https://crrev.com/8a68f8a307ee8b54b70d121130d1414c61a0d3c7/content/renderer/media/stream/media_stream_video_capturer_source.cc
[modify] https://crrev.com/8a68f8a307ee8b54b70d121130d1414c61a0d3c7/content/renderer/media/stream/media_stream_video_source.cc
[modify] https://crrev.com/8a68f8a307ee8b54b70d121130d1414c61a0d3c7/content/renderer/media/stream/mock_media_stream_video_source.cc
[modify] https://crrev.com/8a68f8a307ee8b54b70d121130d1414c61a0d3c7/content/renderer/media/stream/user_media_client_impl_unittest.cc
[modify] https://crrev.com/8a68f8a307ee8b54b70d121130d1414c61a0d3c7/content/renderer/media/stream/user_media_processor.cc
[modify] https://crrev.com/8a68f8a307ee8b54b70d121130d1414c61a0d3c7/content/renderer/media/webrtc/webrtc_uma_histograms.cc
[modify] https://crrev.com/8a68f8a307ee8b54b70d121130d1414c61a0d3c7/tools/metrics/histograms/enums.xml
[modify] https://crrev.com/8a68f8a307ee8b54b70d121130d1414c61a0d3c7/tools/metrics/histograms/histograms.xml