Skip constraint test on firefox <42 (can't turn off constraint-less fake devices).
Skip constraint test on firefox <42 (can't turn off constraint-less fake devices).

Zauberstuhl/adapter,harme199497/adapter,webrtc/adapter,webrtc/adapter,Zauberstuhl/adapter,Zauberstuhl/adapter,calebboyd/adapter,Acidburn0zzz/adapter,4lejandrito/adapter,Acidburn0zzz/adapter,harme199497/adapter,shines/adapter,shines/adapter,harme199497/adapter,xdumaine/adapter,Acidburn0zzz/adapter,4lejandrito/adapter,4lejandrito/adapter,calebboyd/adapter,shines/adapter,xdumaine/adapter,jan-ivar/adapter,jan-ivar/adapter,calebboyd/adapter