src/vs/workbench/services/themes/browser/fileIconThemeData.ts/FileIconThemeData/load
class FileIconThemeData:	private load(fileService: IFileService): Promise<string | undefined> {
		if (!this.location) {
			return Promise.resolve(this.styleSheetContent);
		}
		return _loadIconThemeDocument(fileService, this.location).then(iconThemeDocument => {
			const result = _processIconThemeDocument(this.id, this.location!, iconThemeDocument);
			this.styleSheetContent = result.content;
			this.hasFileIcons = result.hasFileIcons;
			this.hasFolderIcons = result.hasFolderIcons;
			this.hidesExplorerArrows = result.hidesExplorerArrows;
			this.isLoaded = true;
			return this.styleSheetContent;
		});
	}