diff --git a/core/modules/simpletest/src/BrowserTestBase.php b/core/modules/simpletest/src/BrowserTestBase.php
index 2559bb4..8cbfe4a 100644
--- a/core/modules/simpletest/src/BrowserTestBase.php
+++ b/core/modules/simpletest/src/BrowserTestBase.php
@@ -26,8 +26,8 @@
 use Drupal\Core\Test\TestRunnerKernel;
 use Drupal\Core\Url;
 use Drupal\user\UserInterface;
+use Symfony\Component\CssSelector\CssSelector;
 use Symfony\Component\HttpFoundation\Request;
-use Zumba\Mink\Driver\PhantomJSDriver;
 
 /**
  * Provides a test case for functional Drupal tests.
@@ -1364,7 +1364,7 @@ protected function drupalUserIsLoggedIn(UserInterface $account) {
    *   Optional message to show alongside the assertion.
    */
   protected function assertElementPresent($css_selector, $message = '') {
-    $this->assertNotEmpty($this->getSession()->getDriver()->find($this->selectorToXpath($css_selector)), $message);
+    $this->assertNotEmpty($this->getSession()->getDriver()->find(CssSelector::toXPath($css_selector)), $message);
   }
 
   /**
@@ -1376,7 +1376,7 @@ protected function assertElementPresent($css_selector, $message = '') {
    *   Optional message to show alongside the assertion.
    */
   protected function assertElementNotPresent($css_selector, $message = '') {
-    $this->assertEmpty($this->getSession()->getDriver()->find($this->selectorToXpath($css_selector)), $message);
+    $this->assertEmpty($this->getSession()->getDriver()->find(CssSelector::toXPath($css_selector)), $message);
   }
 
   /**
@@ -1386,20 +1386,7 @@ protected function assertElementNotPresent($css_selector, $message = '') {
    *   The CSS selector identifying the element to click.
    */
   protected function click($css_selector) {
-    $this->getSession()->getDriver()->click($this->selectorToXpath($css_selector));
-  }
-
-  /**
-   * Converts the given CSS selector to an XPath expression.
-   *
-   * @param string $css_selector
-   *   The CSS selector to convert.
-   *
-   * @return string
-   *   The converted XPath expression.
-   */
-  protected function selectorToXpath($css_selector) {
-    return $this->getSession()->getSelectorsHandler()->selectorToXpath('css', $css_selector);
+    $this->getSession()->getDriver()->click(CssSelector::toXPath($css_selector));
   }
 
   /**
diff --git a/core/tests/Drupal/FunctionalJavascriptTests/JavascriptTestBase.php b/core/tests/Drupal/FunctionalJavascriptTests/JavascriptTestBase.php
index 29eb744..deeb026 100644
--- a/core/tests/Drupal/FunctionalJavascriptTests/JavascriptTestBase.php
+++ b/core/tests/Drupal/FunctionalJavascriptTests/JavascriptTestBase.php
@@ -3,6 +3,7 @@
 namespace Drupal\FunctionalJavascriptTests;
 
 use Drupal\simpletest\BrowserTestBase;
+use Symfony\Component\CssSelector;
 use Zumba\Mink\Driver\PhantomJSDriver;
 
 /**
@@ -42,7 +43,7 @@ protected function initMink() {
    *   Optional message to show alongside the assertion.
    */
   protected function assertElementVisible($css_selector, $message = '') {
-    $this->assertTrue($this->getSession()->getDriver()->isVisible($this->selectorToXpath($css_selector)), $message);
+    $this->assertTrue($this->getSession()->getDriver()->isVisible(CssSelector::toXPath($css_selector)), $message);
   }
 
   /**
@@ -54,7 +55,7 @@ protected function assertElementVisible($css_selector, $message = '') {
    *   Optional message to show alongside the assertion.
    */
   protected function assertElementNotVisible($css_selector, $message = '') {
-    $this->assertFalse($this->getSession()->getDriver()->isVisible($this->selectorToXpath($css_selector)), $message);
+    $this->assertFalse($this->getSession()->getDriver()->isVisible(CssSelector::toXPath($css_selector)), $message);
   }
 
   /**