[document picture-in-picture] Propagate user activation to the opener
This CL changes browser-process-side user activation logic to allow
activations in document picture-in-picture windows to be used in their
opener windows, and activations in the opener windows to be used in
their document picture-in-picture windows.
This feature is behind an enabled-by-default feature flag.
Specification change:
WICG/document-picture-in-picture#117
Chromestatus: https://chromestatus.com/feature/5185710702460928
Intent to Prototype:
https://groups.google.com/a/chromium.org/g/blink-dev/c/MwH0ODG4bec
Intent to Ship:
https://groups.google.com/a/chromium.org/g/blink-dev/c/AfzrMoCgccQ
Bug: 331246719
Change-Id: Iedad1e0cb60e04fc1ccf350405f04a399a2b72a1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5393891
Commit-Queue: Tommy Steimel steimel@chromium.org
Reviewed-by: Mustaq Ahmed mustaq@chromium.org
Reviewed-by: Daniel Cheng dcheng@chromium.org
Reviewed-by: Alex Moshchuk alexmos@chromium.org
Reviewed-by: Xianzhu Wang wangxianzhu@chromium.org
Cr-Commit-Position: refs/heads/main@{#1304599}