ignore source if the content-type is text/...

Former-commit-id: 8e9e6d00942dcb5791f9db3765ef52d780ce3752

lib/single-file/modules/css-fonts-alt-minifier.js

@@ -37,6 +37,7 @@ this.singlefile.lib.modules.fontsAltMinifier = this.singlefile.lib.modules.fonts
 	const REGEXP_FONT_FORMAT_VALUE = /format\((.*?)\)\s*,?$/;
 	const REGEXP_FONT_SRC = /(.*?)\s*,?$/;
 	const EMPTY_URL_SOURCE = /^url\(["']?data:[^,]*,?["']?\)/;
+	const TEXT_CONTENT_URL_SOURCE = /^url\(["']?data:text\//;
 	const LOCAL_SOURCE = "local(";
 	const MEDIA_ALL = "all";
 	const FONT_WEIGHTS = {
@@ -196,7 +197,7 @@ this.singlefile.lib.modules.fontsAltMinifier = this.singlefile.lib.modules.fonts
 
 	function processFontFaceRule(ruleData, fontInfo, stats) {
 		const cssTree = singlefile.lib.vendor.cssTree;
-		const findSource = fontFormat => fontInfo.find(source => !source.src.match(EMPTY_URL_SOURCE) && source.format == fontFormat);
+		const findSource = fontFormat => fontInfo.find(source => !source.src.match(EMPTY_URL_SOURCE) && !source.src.match(TEXT_CONTENT_URL_SOURCE) && source.format == fontFormat);
 		const filterSource = fontSource => fontInfo.filter(source => source == fontSource || source.src.startsWith(LOCAL_SOURCE));
 		stats.fonts.processed += fontInfo.length;
 		stats.fonts.discarded += fontInfo.length;