Add vjs-scrubbing class to player while scrubbing

[jcaron23]

This is useful to add CSS preventing hover menus from opening while scrubbing, even if the mouse strays out of the seek bar.

[mmcc]

Thank you! Are you just doing this so you can add .vjs-scrubbing styles in your app or did you have default classes in mind?

[heff]

@jcaron23 just following up on this. When I test scrubbing on videojs.com and roll over the captions menu, the menu doesn't show. Is there a live example of this happening, or could we create a jsbin for it?

[jcaron23]

Which browser did you test it on? Safari appears to block :hover while the mouse is down, but Firefox and IE don't. Haven't checked Chrome.

[heff]

Yeah, no issues on Safari or Chrome but I was able to reproduce it on Firefox. Thanks for pointing that out. Would you want to help update the existing menus to use the vis-scrubbing class?

[jcaron23]

I currently use this CSS:
/* prevent menus from opening while scrubbing (FF, IE) */
.vjs-default-skin.vjs-scrubbing .vjs-menu-button:hover .vjs-menu {
display: none;
}

Not quite sure it necessarily fits in the general case.

Also, it might be better to actually have some sort of not-scrubbing class (so we can just have the :hover work only on not-scrubbing, but that probably requires quite a few more changes.

[heff]

Nice, I think the first option looks good to me. Want to add it to the pull request?

[jcaron23]

Added (slightly edited) CSS rule to video-js.less

[heff]

This has been merged into master and will go out with the next release. Thanks Jacques!