code: function parseCSS(file, options) {
          var buildInfo = cache.getCache();
  
          gutil.log(gutil.colors.cyan('parseCSS:'), gutil.colors.green(file.path));
  
          var content = file.contents.toString();
          content = replaceCSSUrl(content, options, buildInfo, file.path);
          content = inlineCSS(file, content, options, buildInfo);
          file.contents = new Buffer(content);
      }
docs: 处理css