message: Add comments from generate_rtl_css.js
diff: @@ -17,10 +17,12 @@ const rtl = require('postcss-rtl');
  const CSS_PROCESSOR = postcss([rtl()]);
  -function processCss(css) {
  +function generateRtlCss(css) {
  return CSS_PROCESSOR.process(css).css
  + // Replace the generated selectors with Shadow DOM selectors for Polymer compatibility.
  .replace(/\[dir=rtl\]/g, ':host(:dir(rtl))')
  .replace(/\[dir=ltr\]/g, ':host(:dir(ltr))')
  + // rtlcss generates [dir] selectors for rules unaffected by directionality; ignore them.
  .replace(/\[dir\]/g, '');
  }
  // This is a Webpack loader that searches for <style> blocks and edits the CSS to support RTL
  @@ -29,7 +31,7 @@ module.exports = function loader(content, map, meta) {
  const callback = this.async();
  const styleRe = RegExp(/(<style[^>]*>)(\s*[^<\s](.*\n)*\s*)(<\/style>)/gm);
  const newContent =
  - content.replace(styleRe, (match, g1, g2, g3, g4) => `${g1}${processCss(g2)}${g4}`);
  + content.replace(styleRe, (match, g1, g2, g3, g4) => `${g1}${generateRtlCss(g2)}${g4}`);
  callback(null, newContent);
  return;
  }
  