Last year Firefox developer Mark Finkle provided an early look at a new feature that would let you stream content from the Firefox mobile browser on your phone to a TV using a Roku. Now it looks like Firefox is adding support for Google Chromecast (and possibly other devices) as well.
According to Mozilla’s weekly meeting notes, Chromecast and Netcast support should be ready by the end of the week.

That doesn’t mean you’ll be able to stream videos from Firefox to a Chromecast right away: the team will still need to test the feature before including it in future builds of Firefox.
You can already use Google’s desktop and mobile versions of the Chrome web browser to stream internet video embedded in a web page to your TV using a Chromecast. But Chrome may not be the only browser with this feature for long.
I can’t find many details about the “Netcast” feature, but the meeting notes refer to a “netcast dongle” and mention that Mark Finkle (the same guy who first showed us tab mirroring in Firefox mobile) is expected to review patches for that dongle. So it seems likely that Google’s Chromecast won’t be the only device supported by the upcoming Firefox video streaming/screen mirroring feature.
via Caschy’s Blog
What happens when Firefox implements its DRM crap? This will stop working will it not?
No. They are unrelated.
From what i can tell, going from anything to Chromecast is easy. But making an alternative to the Chromecast dongle is made very damn hard (at least after the update that allowed third party apps to connect more freely). I got this impression from the guy that developed the Cheapcast Android app that allowed any Android device to pretend to be a Chromecast dongle.