public function optimize(array
$css_assets, array
$libraries) { // Group the assets.
$css_groups =
$this->grouper->
group($css_assets);
// Now optimize (concatenate + minify) and dump each asset group, unless
// that was already done, in which case it should appear in
// drupal_css_cache_files.
// Drupal contrib can override this default CSS aggregator to keep the same
// grouping, optimizing and dumping, but change the strategy that is used to
// determine when the aggregate should be rebuilt (e.g. mtime, HTTPS …).
$map =
$this->state->
get('drupal_css_cache_files',
[]);
$css_assets =
[];
foreach ($css_groups as $order =>
$css_group) { // We have to return a single asset, not a group of assets. It is now up