Fenix issue when coming from PIP: Video is halved.

[Mugurell]

Seen on all Release 97, Beta 98, Nightly 99 (and also on Focus after the PIP integration)
Originally opened a ticket on Bugzilla - https://bugzilla.mozilla.org/show_bug.cgi?id=1757031 since this seems like a GeckoView issue but with the other recent tickets Irelated to fullscreen and screen orientation maybe there is something to improve on Fenix/AC also.

STRs:

• access a youtube video, in my case https://m.youtube.com/watch?v=Aaehn1aY8Ig
• put the video in fullscreen
• press device's home button to enter in Picture in Picture mode
• exit PiP mode, enter the app

Expected result:

• Video is not in fullscreen anymore but do extend to the available GV layout bounds in the app.

Actual result:

• Video is halved (seems like it's width in landscape still occupys what would be screen width while in portrait) but GV does occupy the full width of the screen.
• Also saw another case in which the video is not halved but just smaller - the black bars are larger, maybe such that it would entirely fit the screen, while otherwise it would have to extend to a bit below the visible screen.
• A scroll in the page will have the video immediately take the expected dimensions.

GvVideoFraming.mp4

┆Issue is synchronized with this Jira Story

[Mugurell]

Saw in #22471 that MediaSessionFullscreenFeature might have some issues for certain scenarios, maybe we could also double check our fullscreen/setting orientation functionality separately from GeckoView.

[Mugurell]

This should be fixed by https://bugzilla.mozilla.org/show_bug.cgi?id=1757031

[SoftVision-LorandJanos]

Verified as fixed on the latest Nightly 102.0a1 (2022-05-06) build.
Devices used:

• Samsung Galaxy Tab S3 (Android 9).
• Google Pixel 4 (Android 12).
  Closing the ticket as fixed.