Handle border-image with fill and zero-width borders
Before this patch we require at least one border dimension (top, left,
bottom, right) to be non-zero to trigger the border painting.
This misses the case when we have a zero width border all around but a
border image and border-image-slice: <numbers> fill. The center part
of the border-image should be painted, regardless of the
border-widths.
See
https://bugs.webkit.org/show_bug.cgi?id=142650 and related commit.
It's not an exact port but this patch is heavily inspired by
​sabouhallawa's fix.
BUG=
493088
Committed:
https://src.chromium.org/viewvc/blink?view=rev&revision=196489