Is border-image-slice supported?

HTML

<div class="url number-1"></div>
<div class="linear-gradient number-1"></div>
<div class="radial-gradient number-1"></div>
<div class="url number-2"></div>
<div class="linear-gradient number-2"></div>
<div class="radial-gradient number-2"></div>
<div class="url number-3"></div>
<div class="linear-gradient number-3"></div>
<div class="radial-gradient number-3"></div>
<div class="url number-4"></div>
<div class="linear-gradient number-4"></div>
<div class="radial-gradient number-4"></div>
<div class="url percent-1"></div>
<div class="linear-gradient percent-1"></div>
<div class="radial-gradient percent-1"></div>
<div class="url percent-2"></div>
<div class="linear-gradient percent-2"></div>
<div class="radial-gradient percent-2"></div>
<div class="url percent-2"></div>
<div class="linear-gradient percent-2"></div>
<div class="radial-gradient percent-2"></div>
<div class="url percent-2"></div>
<div class="linear-gradient percent-2"></div>
<div class="radial-gradient percent-2"></div>
<div class="url percent-3"></div>
<div class="linear-gradient percent-3"></div>
<div class="radial-gradient percent-3"></div>
<div class="url percent-3"></div>
<div class="linear-gradient percent-3"></div>
<div class="radial-gradient percent-3"></div>
<div class="url percent-4"></div>
<div class="linear-gradient percent-4"></div>
<div class="radial-gradient percent-4"></div>
<div class="url percent-fill"></div>
<div class="linear-gradient percent-fill"></div>
<div class="radial-gradient percent-fill"></div>
<div class="url number-fill"></div>
<div class="linear-gradient number-fill"></div>
<div class="radial-gradient number-fill"></div>

CSS

div {
    width: 200px;
    height: 200px;
    border: 20px solid red;
    margin: .5em;
}

.url {
    border-image-source: url("https://dl.dropboxusercontent.com/u/444684/openwebref/images/placeholder.png");
}
.linear-gradient {
    border-image-source: linear-gradient(to bottom, blue, green)
}
.radial-gradient {
    border-image-source: radial-gradient(circle, blue, green);
}
.number-1 {
    border-image-slice: 20;
}
.number-2 {
    border-image-slice: 20 40;
}
.number-3 {
    border-image-slice: 20 30 40;
}
.number-4 {
    border-image-slice: 10 20 30 40;
}
.percent-1 {
    border-image-slice: 5%;
}
.percent-2 {
    border-image-slice: 5% 10%;
}
.percent-3 {
    border-image-slice: 5% 10% 15%;
}
.percent-4 {
    border-image-slice: 5% 10% 15% 20%;
}
.percent-fill {
    border-image-slice: 5% fill;
}
.number-fill {
    border-image-slice: 20 fill;
}