fx_cast
Chromecast Web Sender SDK implementation for Firefox
...Clicking on the toolbar button or Cast... menu item in the page context menu will open a popup that shows a list of receiver devices will allow you to start casting the currently detected app2 or media. The extension provides a whitelist for ensuring only trusted sites are allowed to load the cast API and communicate with receiver devices. Sites may be added to the whitelist, either by clicking one of the whitelist options in the toolbar button context menu whilst visiting the site.