Similar to groove/ridge case, inset/outset would scale the color to
decorate the border. Scale fails when the color is black (i.e. zero),
thus this patch will fix this issue by using a fixed color.
Adding inset ref test.
Adding outset ref test.
auto merge of #4437 : Adenilson/servo/fixInsetOutsetBlack03, r=jdm

Freshly rebased.
Update cargo nightly to get android cross compile fix. Also add stub trait method to glutin port.
auto merge of #4438 : glennw/servo/android-fix-1, r=metajack

...it method to glutin port.