code: function inject() {
          if (!WIN || !needsInject) { return }
          needsInject = false;
          var style = Object.keys(byName)
            .map(function (k) { return byName[k]; })
            .concat(remainder).join('\n');
          /* istanbul ignore next */
          if (cssTextProp) { cssTextProp.cssText = style; }
          else { styleNode.innerHTML = style; }
        }
docs: Inject all previously saved tag styles into DOM
  innerHTML seems slow: http://jsperf.com/riot-insert-style