Test calling getPropertyValue on computed styles for -webkit-border-image property.

-webkit-border-image: none;
  -webkit-border-image
    getPropertyValue:    none

-webkit-border-image: linear-gradient(white, black) 25 25 25 25 stretch stretch;
  -webkit-border-image
    getPropertyValue:    linear-gradient(rgb(255, 255, 255), rgb(0, 0, 0)) 25 fill / 1 / 0 stretch

-webkit-border-image: linear-gradient(white, black) 50 repeat;
  -webkit-border-image
    getPropertyValue:    linear-gradient(rgb(255, 255, 255), rgb(0, 0, 0)) 50 fill / 1 / 0 repeat

-webkit-border-image: linear-gradient(white, black) 25 25 25 25 / 20 20 20 20 repeat;
  -webkit-border-image
    getPropertyValue:    linear-gradient(rgb(255, 255, 255), rgb(0, 0, 0)) 25 fill / 20 / 0 repeat

-webkit-border-image: linear-gradient(white, black) 50 / 20 stretch stretch;
  -webkit-border-image
    getPropertyValue:    linear-gradient(rgb(255, 255, 255), rgb(0, 0, 0)) 50 fill / 20 / 0 stretch