Inline @font-face not convert json  #23

@font-face {
font-family: 'NonBreakingSpaceOverride';
src: url(data:application/font-woff2;charset=utf-8;base64,d09GMg...==) format("woff2"),
url(data:application/font-woff;charset=utf-8;base64,d09GR...) format("woff");
}
The css in this structure does not convert to json format correctly.
Example: https://core.trac.wordpress.org/ticket/48062