6 string references to 'drupal_add_css'

CacheTest::testHeaderStorage in drupal/core/modules/views/lib/Drupal/views/Tests/Plugin/CacheTest.php
Tests css/js storage and restoring mechanism.
CascadingStylesheetsTest::setUp in drupal/core/modules/system/lib/Drupal/system/Tests/Common/CascadingStylesheetsTest.php
Sets up a Drupal site for running functional and integration tests.
CascadingStylesheetsTest::testReset in drupal/core/modules/system/lib/Drupal/system/Tests/Common/CascadingStylesheetsTest.php
Makes sure that resetting the CSS empties the cache.
EditController::fieldForm in drupal/core/modules/edit/lib/Drupal/edit/EditController.php
Returns a single field edit form as an Ajax response.
FrameworkTest::testOrder in drupal/core/modules/system/lib/Drupal/system/Tests/Ajax/FrameworkTest.php
Tests AjaxResponse::prepare() AJAX commands ordering.
overlay_render_region in drupal/core/modules/overlay/overlay.module
Renders an individual page region.