GitLab

As discussed: landing behind a flag so we can learn more by testing it
on more Windows laptops. Will eventually be launched using an experiment.
This round is mainly for local testing purposes and to add UMA so we
can track how many devices that support raw audio capture.

NOTRY=true

Tbr: beccahughes
Bug: 1133643
Change-Id: Iae1a5ad45fb8ca7db192e0d3ea779e3803d372d6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2440055Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Reviewed-by: Markus Handell <handellm@google.com>
Reviewed-by: Olga Sharonova <olka@chromium.org>
Reviewed-by: Mark Pearson <mpearson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#812656}