The box should move horizontally 200px over 1s, in 4 equal increments.

PASS - "-webkit-transform.4" property for "box" element at 0.25s saw something close to: 50
PASS - "-webkit-transform.4" property for "box" element at 0.5s saw something close to: 100
PASS - "-webkit-transform.4" property for "box" element at 0.75s saw something close to: 150