Blink will begin to require a border style in order to paint border images. This has always been required by the spec, but has not been enforced. In order to not be affected by this change, add e.g. 'border-style:solid' where border-image is used.
Docs: https://lists.w3.org/Archives/Public/www-style/2015Dec/0080.html
Samples: http://codepen.io/Savago/pen/yYrgyK