Ultimately, there's not even a need to start from scratch on a new engine, #Servo
is pretty far along and having even minimal resources invested into it from outside #Mozilla
would surely help it towards a 1.0 much sooner.
If these companies are willing to work with Google, why not Mozilla?
I realize, it would be more work to get Servo production ready in the short term, but would maintaining a fork of Blink be so much easier as similar user-hostile changes pile up upstream?