window.fullScreen writeable by untrusted content — Mozilla

Mozilla developer Matt Brubeck reported that window.fullScreen is writeable by untrusted content now that the DOM fullscreen API is enabled. Because window.fullScreen does not include mozRequestFullscreen’s security protections, it could be used for UI spoofing. This code change makes window.fullScreen read only by untrusted content, forcing the use of the DOM fullscreen API in normal usage.