convert usedFonts into Array when finished

lib/single-file/util/doc-helper.js

@@ -94,7 +94,7 @@ this.docHelper = this.docHelper || (() => {
 			stylesheetsData: getStylesheetsData(doc),
 			imageData: elementsInfo.imagesData,
 			postersData: elementsInfo.postersData,
-			usedFonts: elementsInfo.usedFonts,
+			usedFonts: Array.from(elementsInfo.usedFonts),
 			shadowRootsData: elementsInfo.shadowRootsData,
 			referrer: doc.referrer
 		};
@@ -141,7 +141,6 @@ this.docHelper = this.docHelper || (() => {
 			}
 			getElementsInfo(win, doc, element, options, data, elementHidden);
 		});
-		data.usedFonts = Array.from(data.usedFonts);
 		return data;
 	}