diff --git a/core/lib/Drupal/Core/Asset/CssCollectionOptimizer.php b/core/lib/Drupal/Core/Asset/CssCollectionOptimizer.php
index 73bac77..5b63897 100644
--- a/core/lib/Drupal/Core/Asset/CssCollectionOptimizer.php
+++ b/core/lib/Drupal/Core/Asset/CssCollectionOptimizer.php
@@ -4,13 +4,17 @@
 
 use Drupal\Core\State\StateInterface;
 
+@trigger_error('The ' . __NAMESPACE__ . '\CssCollectionOptimizer is deprecated in Drupal 8.4.0 and will be removed before Drupal 9.0.0. Instead, use ' . __NAMESPACE__ . '\CssCollectionOptimizerLazy', E_USER_DEPRECATED);
+
 /**
  * Optimizes CSS assets.
  *
  * @deprecated as of Drupal 8.3.x, will be removed before Drupal 9.0.0
+ *   Instead you should use \Drupal\Core\Asset\CssCollectionOptimizerLazy
+ *
+ * @see https://www.drupal.org/node/2888767
  */
 class CssCollectionOptimizer implements AssetCollectionOptimizerInterface {
-  use CssCollectionOptimizerTrait;
 
   /**
    * A CSS asset grouper.
@@ -34,6 +38,20 @@ class CssCollectionOptimizer implements AssetCollectionOptimizerInterface {
   protected $dumper;
 
   /**
+   * The CSS asset optimizer.
+   *
+   * @var \Drupal\Core\Asset\CssOptimizer
+   */
+  protected $optimizer;
+
+  /**
+   * The state key/value store.
+   *
+   * @var \Drupal\Core\State\StateInterface
+   */
+  protected $state;
+
+  /**
    * Constructs a CssCollectionOptimizer.
    *
    * @param \Drupal\Core\Asset\AssetCollectionGrouperInterface $grouper
@@ -146,4 +164,53 @@ protected function generateHash(array $css_group) {
     return hash('sha256', serialize($css_data));
   }
 
+  /**
+   * Optimizes a specific group assets.
+   *
+   * @param array $group
+   *   An asset group.
+   *
+   * @return array
+   *   The optimized string for the group.
+   */
+  public function optimizeGroup(array $group) {
+    // Optimize each asset within the group.
+    $data = '';
+    foreach ($group['items'] as $asset) {
+      $data .= $this->optimizer->optimize($asset);
+    }
+    // Per the W3C specification at
+    // http://www.w3.org/TR/REC-CSS2/cascade.html#at-import, @import
+    // rules must precede any other style, so we move those to the
+    // top.
+    $regexp = '/@import[^;]+;/i';
+    preg_match_all($regexp, $data, $matches);
+    $data = preg_replace($regexp, '', $data);
+    return implode('', $matches[0]) . $data;
+  }
+
+  /**
+   * Deletes all optimized asset collections assets.
+   */
+  public function deleteAll() {
+    $this->state->delete('drupal_css_cache_files');
+    $delete_stale = function($uri) {
+      // Default stale file threshold is 30 days.
+      if (REQUEST_TIME - filemtime($uri) > \Drupal::config('system.performance')->get('stale_file_threshold')) {
+        file_unmanaged_delete($uri);
+      }
+    };
+    file_scan_directory('public://css', '/.*/', array('callback' => $delete_stale));
+  }
+
+  /**
+   * Returns all optimized asset collections assets.
+   *
+   * @return string[]
+   *   URIs for all optimized asset collection assets.
+   */
+ public function getAll() {
+   return $this->state->get('drupal_css_cache_files', []);
+ }
+
 }
diff --git a/core/lib/Drupal/Core/Asset/CssCollectionOptimizerLazy.php b/core/lib/Drupal/Core/Asset/CssCollectionOptimizerLazy.php
index d020e54..715e48d 100644
--- a/core/lib/Drupal/Core/Asset/CssCollectionOptimizerLazy.php
+++ b/core/lib/Drupal/Core/Asset/CssCollectionOptimizerLazy.php
@@ -12,7 +12,6 @@
  */
 class CssCollectionOptimizerLazy implements AssetCollectionGroupOptimizerInterface {
   use AssetGroupSetHashTrait;
-  use CssCollectionOptimizerTrait;
 
   /**
    * The grouper for CSS assets.
@@ -36,6 +35,13 @@ class CssCollectionOptimizerLazy implements AssetCollectionGroupOptimizerInterfa
   protected $dependencyResolver;
 
   /**
+   * The CSS asset optimizer.
+   *
+   * @var \Drupal\Core\Asset\CssOptimizer
+   */
+  protected $optimizer;
+
+  /**
    * The request stack.
    *
    * @var \Symfony\HttpFoundation\RequestStack
@@ -43,6 +49,14 @@ class CssCollectionOptimizerLazy implements AssetCollectionGroupOptimizerInterfa
   protected $requestStack;
 
   /**
+   * The state key/value store.
+   *
+   * @var \Drupal\Core\State\StateInterface
+   */
+  protected $state;
+
+
+  /**
    * Constructs a CssCollectionOptimizerLazy.
    *
    * @param \Drupal\Core\Asset\AssetCollectionGrouperInterface $grouper
@@ -141,5 +155,53 @@ public function optimize(array $css_assets) {
     return $css_assets;
   }
 
+  /**
+   * Optimizes a specific group assets.
+   *
+   * @param array $group
+   *   An asset group.
+   *
+   * @return array
+   *   The optimized string for the group.
+   */
+  public function optimizeGroup(array $group) {
+    // Optimize each asset within the group.
+    $data = '';
+    foreach ($group['items'] as $asset) {
+      $data .= $this->optimizer->optimize($asset);
+    }
+    // Per the W3C specification at
+    // http://www.w3.org/TR/REC-CSS2/cascade.html#at-import, @import
+    // rules must precede any other style, so we move those to the
+    // top.
+    $regexp = '/@import[^;]+;/i';
+    preg_match_all($regexp, $data, $matches);
+    $data = preg_replace($regexp, '', $data);
+    return implode('', $matches[0]) . $data;
+  }
+
+  /**
+   * Deletes all optimized asset collections assets.
+   */
+  public function deleteAll() {
+    $this->state->delete('drupal_css_cache_files');
+    $delete_stale = function($uri) {
+      // Default stale file threshold is 30 days.
+      if (REQUEST_TIME - filemtime($uri) > \Drupal::config('system.performance')->get('stale_file_threshold')) {
+        file_unmanaged_delete($uri);
+      }
+    };
+    file_scan_directory('public://css', '/.*/', array('callback' => $delete_stale));
+  }
+
+  /**
+   * Returns all optimized asset collections assets.
+   *
+   * @return string[]
+   *   URIs for all optimized asset collection assets.
+   */
+ public function getAll() {
+   return $this->state->get('drupal_css_cache_files', []);
+ }
 
 }
diff --git a/core/lib/Drupal/Core/Asset/CssCollectionOptimizerTrait.php b/core/lib/Drupal/Core/Asset/CssCollectionOptimizerTrait.php
deleted file mode 100644
index e884003..0000000
--- a/core/lib/Drupal/Core/Asset/CssCollectionOptimizerTrait.php
+++ /dev/null
@@ -1,73 +0,0 @@
-<?php
-
-namespace Drupal\Core\Asset;
-
-/**
- * Optimizes CSS assets.
- */
-trait CssCollectionOptimizerTrait {
-
-  /**
-   * The CSS asset optimizer.
-   *
-   * @var \Drupal\Core\Asset\CssOptimizer
-   */
-  protected $optimizer;
-
-  /**
-   * The state key/value store.
-   *
-   * @var \Drupal\Core\State\StateInterface
-   */
-  protected $state;
-
-  /**
-   * Optimizes a specific group assets.
-   *
-   * @param array $group
-   *   An asset group.
-   *
-   * @return array
-   *   The optimized string for the group.
-   */
-  public function optimizeGroup(array $group) {
-    // Optimize each asset within the group.
-    $data = '';
-    foreach ($group['items'] as $asset) {
-      $data .= $this->optimizer->optimize($asset);
-    }
-    // Per the W3C specification at
-    // http://www.w3.org/TR/REC-CSS2/cascade.html#at-import, @import
-    // rules must precede any other style, so we move those to the
-    // top.
-    $regexp = '/@import[^;]+;/i';
-    preg_match_all($regexp, $data, $matches);
-    $data = preg_replace($regexp, '', $data);
-    return implode('', $matches[0]) . $data;
-  }
-
-  /**
-   * Deletes all optimized asset collections assets.
-   */
-  public function deleteAll() {
-    $this->state->delete('drupal_css_cache_files');
-    $delete_stale = function($uri) {
-      // Default stale file threshold is 30 days.
-      if (REQUEST_TIME - filemtime($uri) > \Drupal::config('system.performance')->get('stale_file_threshold')) {
-        file_unmanaged_delete($uri);
-      }
-    };
-    file_scan_directory('public://css', '/.*/', array('callback' => $delete_stale));
-  }
-
-  /**
-   * Returns all optimized asset collections assets.
-   *
-   * @return string[]
-   *   URIs for all optimized asset collection assets.
-   */
- public function getAll() {
-   return $this->state->get('drupal_css_cache_files', []);
- }
-
-}
diff --git a/core/lib/Drupal/Core/Asset/JsCollectionOptimizer.php b/core/lib/Drupal/Core/Asset/JsCollectionOptimizer.php
index f82c5bc..20e0938 100644
--- a/core/lib/Drupal/Core/Asset/JsCollectionOptimizer.php
+++ b/core/lib/Drupal/Core/Asset/JsCollectionOptimizer.php
@@ -4,14 +4,18 @@
 
 use Drupal\Core\State\StateInterface;
 
+@trigger_error('The ' . __NAMESPACE__ . '\JsCollectionOptimizer is deprecated in Drupal 8.4.0 and will be removed before Drupal 9.0.0. Instead, use ' . __NAMESPACE__ . '\JsCollectionOptimizerLazy', E_USER_DEPRECATED);
+
 /**
  * Optimizes JavaScript assets.
  *
  * @deprecated as of Drupal 8.3.x, will be removed before Drupal 9.0.0
+ *   Instead you should use \Drupal\Core\Asset\JsCollectionOptimizerLazy
+ *
+ * @see https://www.drupal.org/node/2888767
  *
  */
 class JsCollectionOptimizer implements AssetCollectionOptimizerInterface {
-  use JsCollectionOptimizerTrait;
 
   /**
    * A JS asset grouper.
@@ -35,6 +39,20 @@ class JsCollectionOptimizer implements AssetCollectionOptimizerInterface {
   protected $dumper;
 
   /**
+   * A JS asset optimizer.
+   *
+   * @var \Drupal\Core\Asset\AssetOptimizerInterface
+   */
+  protected $optimizer;
+
+  /**
+   * The state key/value store.
+   *
+   * @var \Drupal\Core\State\StateInterface
+   */
+  protected $state;
+
+  /**
    * Constructs a JsCollectionOptimizer.
    *
    * @param \Drupal\Core\Asset\AssetCollectionGrouperInterface $grouper
@@ -147,4 +165,54 @@ protected function generateHash(array $js_group) {
     return hash('sha256', serialize($js_data));
   }
 
+  /**
+   * Optimizes a specific group assets.
+   *
+   * @param array $group
+   *   An asset group.
+   *
+   * @return array
+   *   The optimized string for the group.
+   */
+  public function optimizeGroup(array $group) {
+    $data = '';
+    foreach ($group['items'] as $js_asset) {
+      // Optimize this JS file, but only if it's not yet minified.
+      if (isset($js_asset['minified']) && $js_asset['minified']) {
+        $data .= file_get_contents($js_asset['data']);
+      }
+      else {
+        $data .= $this->optimizer->optimize($js_asset);
+      }
+      // Append a ';' and a newline after each JS file to prevent them from
+      // running together.
+      $data .= ";\n";
+    }
+    // Remove unwanted JS code that cause issues.
+    return $this->optimizer->clean($data);
+  }
+
+  /**
+   * Deletes all optimized asset collections assets.
+   */
+  public function deleteAll() {
+    $this->state->delete('system.js_cache_files');
+    $delete_stale = function($uri) {
+      // Default stale file threshold is 30 days.
+      if (REQUEST_TIME - filemtime($uri) > \Drupal::config('system.performance')->get('stale_file_threshold')) {
+        file_unmanaged_delete($uri);
+      }
+    };
+    file_scan_directory('public://js', '/.*/', array('callback' => $delete_stale));
+  }
+
+  /**
+   * Returns all optimized asset collections assets.
+   *
+   * @return string[]
+   *   URIs for all optimized asset collection assets.
+   */
+  public function getAll() {
+    return $this->state->get('system.js_cache_files', []);
+  }
 }
diff --git a/core/lib/Drupal/Core/Asset/JsCollectionOptimizerLazy.php b/core/lib/Drupal/Core/Asset/JsCollectionOptimizerLazy.php
index e355078..607d509 100644
--- a/core/lib/Drupal/Core/Asset/JsCollectionOptimizerLazy.php
+++ b/core/lib/Drupal/Core/Asset/JsCollectionOptimizerLazy.php
@@ -13,7 +13,6 @@
  */
 class JsCollectionOptimizerLazy implements AssetCollectionGroupOptimizerInterface {
   use AssetGroupSetHashTrait;
-  use JsCollectionOptimizerTrait;
 
   /**
    * A JS asset grouper.
@@ -44,6 +43,21 @@ class JsCollectionOptimizerLazy implements AssetCollectionGroupOptimizerInterfac
   protected $requestStack;
 
   /**
+   * A JS asset optimizer.
+   *
+   * @var \Drupal\Core\Asset\AssetOptimizerInterface
+   */
+  protected $optimizer;
+
+  /**
+   * The state key/value store.
+   *
+   * @var \Drupal\Core\State\StateInterface
+   */
+  protected $state;
+
+
+  /**
    * Constructs a JsCollectionOptimizerLazy.
    *
    * @param \Drupal\Core\Asset\AssetCollectionGrouperInterface $grouper
@@ -150,4 +164,55 @@ public function optimize(array $js_assets) {
     return $js_assets;
   }
 
+  /**
+   * Optimizes a specific group assets.
+   *
+   * @param array $group
+   *   An asset group.
+   *
+   * @return array
+   *   The optimized string for the group.
+   */
+  public function optimizeGroup(array $group) {
+    $data = '';
+    foreach ($group['items'] as $js_asset) {
+      // Optimize this JS file, but only if it's not yet minified.
+      if (isset($js_asset['minified']) && $js_asset['minified']) {
+        $data .= file_get_contents($js_asset['data']);
+      }
+      else {
+        $data .= $this->optimizer->optimize($js_asset);
+      }
+      // Append a ';' and a newline after each JS file to prevent them from
+      // running together.
+      $data .= ";\n";
+    }
+    // Remove unwanted JS code that cause issues.
+    return $this->optimizer->clean($data);
+  }
+
+  /**
+   * Deletes all optimized asset collections assets.
+   */
+  public function deleteAll() {
+    $this->state->delete('system.js_cache_files');
+    $delete_stale = function($uri) {
+      // Default stale file threshold is 30 days.
+      if (REQUEST_TIME - filemtime($uri) > \Drupal::config('system.performance')->get('stale_file_threshold')) {
+        file_unmanaged_delete($uri);
+      }
+    };
+    file_scan_directory('public://js', '/.*/', array('callback' => $delete_stale));
+  }
+
+  /**
+   * Returns all optimized asset collections assets.
+   *
+   * @return string[]
+   *   URIs for all optimized asset collection assets.
+   */
+  public function getAll() {
+    return $this->state->get('system.js_cache_files', []);
+  }
+
 }
diff --git a/core/lib/Drupal/Core/Asset/JsCollectionOptimizerTrait.php b/core/lib/Drupal/Core/Asset/JsCollectionOptimizerTrait.php
deleted file mode 100644
index 9bea1a8..0000000
--- a/core/lib/Drupal/Core/Asset/JsCollectionOptimizerTrait.php
+++ /dev/null
@@ -1,78 +0,0 @@
-<?php
-
-namespace Drupal\Core\Asset;
-
-use Drupal\Core\State\StateInterface;
-
-/**
- * Optimizes JavaScript assets.
- */
-trait JsCollectionOptimizerTrait {
-
-  /**
-   * A JS asset optimizer.
-   *
-   * @var \Drupal\Core\Asset\AssetOptimizerInterface
-   */
-  protected $optimizer;
-
-  /**
-   * The state key/value store.
-   *
-   * @var \Drupal\Core\State\StateInterface
-   */
-  protected $state;
-
-  /**
-   * Optimizes a specific group assets.
-   *
-   * @param array $group
-   *   An asset group.
-   *
-   * @return array
-   *   The optimized string for the group.
-   */
-  public function optimizeGroup(array $group) {
-    $data = '';
-    foreach ($group['items'] as $js_asset) {
-      // Optimize this JS file, but only if it's not yet minified.
-      if (isset($js_asset['minified']) && $js_asset['minified']) {
-        $data .= file_get_contents($js_asset['data']);
-      }
-      else {
-        $data .= $this->optimizer->optimize($js_asset);
-      }
-      // Append a ';' and a newline after each JS file to prevent them from
-      // running together.
-      $data .= ";\n";
-    }
-    // Remove unwanted JS code that cause issues.
-    return $this->optimizer->clean($data);
-  }
-
-  /**
-   * Deletes all optimized asset collections assets.
-   */
-  public function deleteAll() {
-    $this->state->delete('system.js_cache_files');
-    $delete_stale = function($uri) {
-      // Default stale file threshold is 30 days.
-      if (REQUEST_TIME - filemtime($uri) > \Drupal::config('system.performance')->get('stale_file_threshold')) {
-        file_unmanaged_delete($uri);
-      }
-    };
-    file_scan_directory('public://js', '/.*/', array('callback' => $delete_stale));
-  }
-
-  /**
-   * Returns all optimized asset collections assets.
-   *
-   * @return string[]
-   *   URIs for all optimized asset collection assets.
-   */
-  public function getAll() {
-    return $this->state->get('system.js_cache_files', []);
-  }
-
-
-}