executes chrome on travis CI; for browser tests.

chromOnTravis

// This block is needed to execute Chrome on Travis
// If you ever plan to use Chrome and Travis, you can keep it
// If not, you can safely remove it
// https://github.com/karma-runner/karma/issues/1144#issuecomment-53633076
if(configuration.browsers[0] === 'Chrome' && process.env.TRAVIS) {
  configuration.customLaunchers = {
    'chrome-travis-ci': {
      base: 'Chrome',
      flags: ['--no-sandbox']
    }
  };
  configuration.browsers = ['chrome-travis-ci'];
}