The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b27097187d8c503cd0b112bb99e4489db874ac3a

commit b27097187d8c503cd0b112bb99e4489db874ac3a
Author: Guido Urdaneta <guidou@chromium.org>
Date: Mon Sep 03 13:18:55 2018

Remove support for googPowerLineFrequency in getUserMedia()

This constrainable property is nonstandard, only supported with the
deprecated syntax, and rarely used.

This change does not remove the property from the Web, but disables its
effects and prints a console message instead, similar to other
similar properties.

Drive-by: minor lint fixes.

Bug:  880032 
Change-Id: I197428ca76594389193351f8a9ea55b11d2419e5
Reviewed-on: https://chromium-review.googlesource.com/1201861
Reviewed-by: Harald Alvestrand <hta@chromium.org>
Reviewed-by: Philip Jägenstedt <foolip@chromium.org>
Commit-Queue: Guido Urdaneta <guidou@chromium.org>
Cr-Commit-Position: refs/heads/master@{#588380}
[modify] https://crrev.com/b27097187d8c503cd0b112bb99e4489db874ac3a/content/renderer/media/stream/apply_constraints_processor.cc
[modify] https://crrev.com/b27097187d8c503cd0b112bb99e4489db874ac3a/content/renderer/media/stream/media_stream_constraints_util.h
[modify] https://crrev.com/b27097187d8c503cd0b112bb99e4489db874ac3a/content/renderer/media/stream/media_stream_constraints_util_video_device.cc
[modify] https://crrev.com/b27097187d8c503cd0b112bb99e4489db874ac3a/content/renderer/media/stream/media_stream_constraints_util_video_device.h
[modify] https://crrev.com/b27097187d8c503cd0b112bb99e4489db874ac3a/content/renderer/media/stream/media_stream_constraints_util_video_device_unittest.cc
[modify] https://crrev.com/b27097187d8c503cd0b112bb99e4489db874ac3a/content/renderer/media/stream/user_media_client_impl_unittest.cc
[modify] https://crrev.com/b27097187d8c503cd0b112bb99e4489db874ac3a/content/renderer/media/stream/user_media_processor.cc
[modify] https://crrev.com/b27097187d8c503cd0b112bb99e4489db874ac3a/third_party/blink/public/platform/web_feature.mojom
[modify] https://crrev.com/b27097187d8c503cd0b112bb99e4489db874ac3a/third_party/blink/public/platform/web_media_constraints.h
[modify] https://crrev.com/b27097187d8c503cd0b112bb99e4489db874ac3a/third_party/blink/renderer/modules/mediastream/media_constraints_impl.cc
[modify] https://crrev.com/b27097187d8c503cd0b112bb99e4489db874ac3a/third_party/blink/renderer/modules/mediastream/user_media_request.cc
[modify] https://crrev.com/b27097187d8c503cd0b112bb99e4489db874ac3a/third_party/blink/renderer/platform/exported/web_media_constraints.cc