code: function (startDir, config) {
              var buildText = "",
                  importList = [],
                  shouldRemove = config.dir && config.removeCombined,
                  i, fileName, result, fileList;
              if (config.optimizeCss.indexOf("standard") !== -1) {
                  fileList = file.getFilteredFileList(startDir, /\.css$/, true);
                  if (fileList) {
                      for (i = 0; i < fileList.length; i++) {
                          fileName = fileList[i];
                          logger.trace("Optimizing (" + config.optimizeCss + ") CSS file: " + fileName);
                          result = optimize.cssFile(fileName, fileName, config);
                          buildText += result.buildText;
                          if (shouldRemove) {
                              result.importList.pop();
                              importList = importList.concat(result.importList);
                          }
                      }
                  }
  
                  if (shouldRemove) {
                      importList.forEach(function (path) {
                          if (file.exists(path)) {
                              file.deleteFile(path);
                          }
                      });
                  }
              }
              return buildText;
          }
docs: Optimizes CSS files, inlining @import calls, stripping comments, and
  optionally removes line returns.
  @param {String} startDir the path to the top level directory
  @param {Object} config the config object with the optimizeCss and
  cssImportIgnore options.