The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0ab64718fc3ad72ce22b284ab1c0791c2ba4cfc8

commit 0ab64718fc3ad72ce22b284ab1c0791c2ba4cfc8
Author: Max Morin <maxmorin@chromium.org>
Date: Mon Jun 25 17:51:59 2018

Remove googBeamforming and googArrayGeometry.

Drive-by fix some lint.

Bug:  851940 ,  856176 
Change-Id: Ia42c0902b58cd278afc2c4703a50982204ef75b8
Reviewed-on: https://chromium-review.googlesource.com/1099235
Commit-Queue: Max Morin <maxmorin@chromium.org>
Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Reviewed-by: Philip Jägenstedt <foolip@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570088}
[modify] https://crrev.com/0ab64718fc3ad72ce22b284ab1c0791c2ba4cfc8/content/renderer/media/stream/media_stream_audio_processor.cc
[modify] https://crrev.com/0ab64718fc3ad72ce22b284ab1c0791c2ba4cfc8/content/renderer/media/stream/media_stream_audio_processor_options.cc
[modify] https://crrev.com/0ab64718fc3ad72ce22b284ab1c0791c2ba4cfc8/content/renderer/media/stream/media_stream_audio_processor_options.h
[modify] https://crrev.com/0ab64718fc3ad72ce22b284ab1c0791c2ba4cfc8/content/renderer/media/stream/media_stream_constraints_util_audio.cc
[modify] https://crrev.com/0ab64718fc3ad72ce22b284ab1c0791c2ba4cfc8/content/renderer/media/stream/media_stream_constraints_util_audio_unittest.cc
[modify] https://crrev.com/0ab64718fc3ad72ce22b284ab1c0791c2ba4cfc8/content/renderer/media/stream/mock_constraint_factory.cc
[modify] https://crrev.com/0ab64718fc3ad72ce22b284ab1c0791c2ba4cfc8/content/renderer/media/stream/user_media_client_impl_unittest.cc
[modify] https://crrev.com/0ab64718fc3ad72ce22b284ab1c0791c2ba4cfc8/media/base/audio_point.cc
[modify] https://crrev.com/0ab64718fc3ad72ce22b284ab1c0791c2ba4cfc8/media/base/audio_point.h
[modify] https://crrev.com/0ab64718fc3ad72ce22b284ab1c0791c2ba4cfc8/media/base/audio_point_unittest.cc
[modify] https://crrev.com/0ab64718fc3ad72ce22b284ab1c0791c2ba4cfc8/third_party/blink/public/platform/web_media_constraints.h
[modify] https://crrev.com/0ab64718fc3ad72ce22b284ab1c0791c2ba4cfc8/third_party/blink/renderer/modules/mediastream/media_constraints_impl.cc
[modify] https://crrev.com/0ab64718fc3ad72ce22b284ab1c0791c2ba4cfc8/third_party/blink/renderer/modules/mediastream/user_media_request.cc
[modify] https://crrev.com/0ab64718fc3ad72ce22b284ab1c0791c2ba4cfc8/third_party/blink/renderer/platform/exported/web_media_constraints.cc

The old-style constraints have always rejected on unknown constraint names in mandatory constraints. They are not specified in the standard, so the spec has no power over them.

If we remove the special cases for googBeamforming and googArrayGeometry, clients that previously worked will start failing.

If we remove the error return, clients that previously used this to probe for unimplemeted constraints will start seeing their detection code break.

Suggestion: Add an UMA counter to the "unimplemented" branch, and let it remain in the code. (Also add an UMA counter to the "error" and "unimplemented but ignored" branches at the end of the ParseOldStyleNames function)

We have implemented this in accordance to #3 and that is enough to consider this work as finished.
In a later stage we will hopefully remove old-style constraints completely, but no further work is needed for googBeamforming and googArrayGeometry.