Do not serve devicePixelRatio to safari 9.1 or iOS 9.3 (#1407)
Do not serve devicePixelRatio to safari 9.1 or iOS 9.3 (#1407)

Compatibility information gathered from https://developer.mozilla.org/en-US/docs/Web/API/Window/devicePixelRatio#Browser_compatibility.

Fixes #1406
JakeChampion/polyfill-service,JakeChampion/polyfill-service