code: function () {
  
          var that = this;
          var base = this.base;
          var $ = this.$;
          var files = [];
  
  
          $('link[rel=stylesheet]').each(function () {
  
              var $this = $(this);
              var cssFile;
              var href = $this.attr('href');
  
              cssFile = utils.resolve(base, href);
              cssFile = getUrl(cssFile);
  
              // 注意：为空也得放进去，保持与 link 标签一一对应
              files.push(cssFile);
          });
  
  
          // 转换 file 地址
          // 执行顺序：ignore > map > normalize
          function getUrl (file) {
  
              if (!that.ignore(file)) {
                  file = that.map(file);
                  file = utils.normalize(file);
                  return file;
              }
          }
  
  
          if (this.options.debug) {
              console.log('');
              console.log('[DEBUG]', 'HtmlParser#getCssFiles', this.file);
              console.log(files);
          }
  
  
          return files;
      }
docs: /*
  获取 CSS 文件地址队列
  @return  {Array}