add support for local videos played in chrome

[test-n-prod]

the extension doesn't detect that there's a video playing when you provide a filepath in the omnibar and play a video this way. this is useful when using chrome to chromecast a local video to a tv

[gignupg]

Interesting! I've never used Chromecast, that's probably why I never noticed this issue. If you want to do a PR, I'll gladly accept it!

[sup3rn0v]

Hello, Happy New Year and thanks a lot for the extension, guys. I am playing the following video but the Chrome extension doesn't detect it https://www.tv5unis.ca/videos/le-bureau-des-legendes/saisons/1/episodes/1
I wanted to use the extension for the English subs. Much appreciated!

[gignupg]

Happy New Year @sup3rn0v, I tried opening your link on my computer and it works flawlessly.