message: refactor(docs-infra): switch `test-pwa-score` to use headless Chrome
  This is slightly faster (15%-20%). Currently, this doesn't make a
  noticeable difference, since the total time is 10s-15s, but it might
  add up, if we decide to run audits on multiple pages.
  PR Close
diff: @@ -19,7 +19,7 @@ const printer = require('lighthouse/lighthouse-cli/printer');
  const logger = require('lighthouse-logger');
  // Constants
  -const CHROME_LAUNCH_OPTS = {};
  +const CHROME_LAUNCH_OPTS = {chromeFlags: ['--headless']};
  const LIGHTHOUSE_FLAGS = {logLevel: 'info'};
  const SKIPPED_HTTPS_AUDITS = ['redirects-http', 'uses-http2'];
  const VIEWER_URL = 'https://googlechrome.github.io/lighthouse/viewer/';
  