www/chromium: Un-remove v4l video capture support

[cem]

Summary

This support was removed in r416521. The revision message did not document the
removal nor justify patching out a major port feature.

This restores that support.

PR 245250

[cem]

We may be missing a DEPEND line on libv4l. Poudriere testport should shake that out, when someone gets a chance.

[saper_saper.info]

In D24330#535212, @cem wrote:

We may be missing a DEPEND line on libv4l. Poudriere testport should shake that out, when someone gets a chance.

It just needs header files from multimedia/v4l_compat - chromium opens the device and issues ioctl()s directly (there is a build dependency already)

[cem]

In D24330#535216, @saper_saper.info wrote:

It just needs header files from multimedia/v4l_compat - chromium opens the device and issues ioctl()s directly (there is a build dependency already)

Even better, thanks!

[jrm]

Thanks Conrad. poudriere testport for 11i386 and 12amd64 passed.

[saper_saper.info]

I have tried this and indeed it now allows me to enable the webcam. However, it the picture is flashed over with a green background few times a second and it produces the following (possibly unrelated) error message one the console:

31511:100555:0409/193333.725369:ERROR:gl_surface_presentation_helper.cc(259)] GetVSyncParametersIfAvailable() failed for 1 times!

[cem]

In D24330#535678, @saper_saper.info wrote:

I have tried this and indeed it now allows me to enable the webcam. However, it the picture is flashed over with a green background few times a second and it produces the following (possibly unrelated) error message one the console:

31511:100555:0409/193333.725369:ERROR:gl_surface_presentation_helper.cc(259)] GetVSyncParametersIfAvailable() failed for 1 times!

Thanks. Would you mind filing a PR to track this issue? I can't promise I am familiar enough with Chrome to debug, and I don't have working webcam myself, but maybe someone else can investigate. I know @kevans had some success using his webcam after this change, but perhaps he had similar problems?

I guess other interesting diagnostics might be, can you reproduce the problem in other webcam-consuming applications (cheese is the only one I know of)?

FWIW, Matthias has an update to Chrome stable 81.x is in the works; if this is some upstream chrome bug, that update may address it. (Maybe not.)

[jrm]

Here is another data point. The webcam in chromium-80.0.3987.163_1 works for me when using https://meet.jit.si/.

[kevans]

In D24330#535678, @saper_saper.info wrote:

I have tried this and indeed it now allows me to enable the webcam. However, it the picture is flashed over with a green background few times a second and it produces the following (possibly unrelated) error message one the console:

31511:100555:0409/193333.725369:ERROR:gl_surface_presentation_helper.cc(259)] GetVSyncParametersIfAvailable() failed for 1 times!

I'll try this out again when I return home (~8 hours); I do not recall seeing any weird artifacts or anything of the sort, but I didn't test it for long.

[saper_saper.info]

Done, https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=245505