[headless] Refactor full screen request handling
https://crrev.com/c/6021359 introduced headless screen support
including multiple screens option.
This CL makes element.requestFullscreen() API headless screen
size aware including the case when the requesting page is located
on a secondary screen.
Change-Id: Ica5411f050b9a9ff00a0511355ce79f796e96850
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6047897
Commit-Queue: Peter Kvitek kvitekp@chromium.org
Reviewed-by: Dmitry Gozman dgozman@chromium.org
Cr-Commit-Position: refs/heads/main@{#1388806}