1178084 - document.mozCancelFullScreen no longer works

Status: RESOLVED DUPLICATE of bug 1178365

(Firefox for Android Graveyard :: Audio/Video, defect)

Description

[Jan Manthay]

Firefox Nightly, build from at least 24. june onwards.

Open:

http://www.tagesschau.de/wirtschaft/ezb-griechenland-109.html
Play the video
Try to start the fullscreen mode of the video

or

http://ritastatusreport.blogspot.nl/2015/06/0910-pearl-river-changes-video.html
Start the embedded Youtube Video.
Try to start fullscreen mode.

Effect:
Not the video, but Firefox goes into fullscreen mode. Awesomebar is deactivated. The video stays in its frame. Trying to deactivate fullscreen mode has no effect, and in one case even crashed Fx: https://crash-stats.mozilla.com/report/index/8f55ebbc-018a-4583-a570-7964c2150628
Using the "back" button of the device loads the previous page, still with no Awesomebar, making one unable to navigate.
Fx has to be shut down forcefully.

Comment 1

[Kevin Brosnan [Ex-Mozilla]]

Related to Bug 1174784?

Comment 2

[Mike Taylor [:miketaylr]]

tagesschau.de is using a JS library called "projekktor" (maybe homebrew?) http://www.tagesschau.de/resources/framework/mediaplayer/js/projekktor-1.4.01.ndr.min.js.

I can confirm that 38.0.5 can fullscreen and back w/o a problem, while Nightly just fullscreens the viewport and gets "stuck" (which is weird?). Possibly related to some UA string sniffing code to determine whether to fake fullscreen or use a native API (though the old prefixed one): https://gist.github.com/miketaylr/d8f83fa81170cf0d61dd. Though that snippet tries to figure it out via feature detection.

Same thing for the Youtube video embed, which is curious.

Bug 1161802 touched fullscreen code, but I don't know if/how that affects Fennec.

Comment 3

[Mike Taylor [:miketaylr]]

Gonna try to make a minimal test case.

Comment 4

[Mike Taylor [:miketaylr]]

Actually, no need. 

STR:
1) visit http://robnyman.github.io/fullscreen/ 
2) hit "Fullscreen" button
3) push hardware back button to exit

Expected:
Full screen exits, stay on demo page

Actual:
Go back in history and browser chrome is missing.

So, not related to UA changes or overrides.

Comment 5

[Mike Taylor [:miketaylr]]

OK, actually made a minimal test case here. 

STR: 
1) Go to URL https://miketaylr.com/bzla/fullscreen.html
2) Click left "enter fullscreen" box
3) When in fullscreen, click right "exit fullscreen" box

EXPECTED:
Fullscreen exits

ACTUAL:
Nothing. No errors in console.

If you hit "back" via the physical button, you can traverse history but the browser chrome is gone because you're still in a fullscreen state. The menu button doesn't work, I assume because that's how fullscreen works(?). You have to close the app to get your browser chrome back.

tl;dr Entering fullscreen works as expected, via elem.mozRequestFullScreen. document.mozCancelFullScreen does nothing.

Comment 6

[Mike Taylor [:miketaylr]]

Actually, snorp already filed this.