AFAIK that's not actually true, one option they have is going through Mesa's llvmpipe in such cases. EDIT: to be clear, with the Servo nightlies you need to do

AFAIK that's not actually true, one option they have is going through Mesa's llvmpipe in such cases. EDIT: to be clear, with the Servo nightlies you need to do this yourself but Firefox could bundle it eventually.