Surface within DevTools AutoPiP for media playback conditions

This information will help developers identify why a picture in picture
window was/was not opened automatically for media playback.

This CL only plumbs the AutoPiP reason, a follow up CL will add the
remaining conditions.

Bug: 368058093, 386193409
Change-Id: I5bff670c357b041c047bd2c7536a9899abd28c49
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6368240
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Bo Liu <boliu@chromium.org>
Commit-Queue: Benjamin Keen <bkeen@google.com>
Reviewed-by: Tommy Steimel <steimel@chromium.org>
Reviewed-by: Ken Buchanan <kenrb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1441683}