If you’re a fan of Firefox for Android, you should be pleased to note that the application is bringing Chromecast support to the release versions.
Currently, support is only available for the nightly builds but it’s expected it will be wending its way into the main channel soon enough.
In the meantime, you can head over to the Firefox nightly builds page, and grab yourself a copy of the Android ARM or x86 versions. If you’re not sure which version of Android you have, you have ARM.
I’m uncertain at the moment if you have to have a copy of the Chromecast app that works with screen mirroring or not to make this work. My assumption is not, but if I’m wrong shoot me a comment and I’ll modify this. (Unfortunately I’m about 16 miles from my Chromecasts at the moment and can’t play around with this, so will have to just wait until I get back.)