only in patch2:
unchanged:
--- a/core/lib/Drupal/Core/Config/StorageComparer.php
+++ b/core/lib/Drupal/Core/Config/StorageComparer.php
@@ -2,6 +2,7 @@
 
 namespace Drupal\Core\Config;
 
+use Drupal\Component\Serialization\PhpSerialize;
 use Drupal\Core\Cache\MemoryBackend;
 use Drupal\Core\Config\Entity\ConfigDependencyManager;
 use Drupal\Core\DependencyInjection\DependencySerializationTrait;
@@ -99,14 +100,17 @@ class StorageComparer implements StorageComparerInterface {
    *   The configuration manager.
    */
   public function __construct(StorageInterface $source_storage, StorageInterface $target_storage, ConfigManagerInterface $config_manager) {
+    // @todo All these direct object initializations are bypassing the service
+    //   configurations. That has to be fixed.
+    $php_serialize = new PhpSerialize();
     // Wrap the storages in a static cache so that multiple reads of the same
     // raw configuration object are not costly.
-    $this->sourceCacheStorage = new MemoryBackend();
+    $this->sourceCacheStorage = new MemoryBackend($php_serialize);
     $this->sourceStorage = new CachedStorage(
       $source_storage,
       $this->sourceCacheStorage
     );
-    $this->targetCacheStorage = new MemoryBackend();
+    $this->targetCacheStorage = new MemoryBackend($php_serialize);
     $this->targetStorage = new CachedStorage(
       $target_storage,
       $this->targetCacheStorage
only in patch2:
unchanged:
--- a/core/tests/Drupal/KernelTests/Core/Cache/BackendChainTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Cache/BackendChainTest.php
@@ -17,9 +17,9 @@ protected function createCacheBackend($bin) {
 
     // We need to create some various backends in the chain.
     $chain
-      ->appendBackend(new MemoryBackend())
-      ->prependBackend(new MemoryBackend())
-      ->appendBackend(new MemoryBackend());
+      ->appendBackend(new MemoryBackend(\Drupal::service('serialization.phpserialize')))
+      ->prependBackend(new MemoryBackend(\Drupal::service('serialization.phpserialize')))
+      ->appendBackend(new MemoryBackend(\Drupal::service('serialization.phpserialize')));
 
     \Drupal::service('cache_tags.invalidator')->addInvalidator($chain);
 
only in patch2:
unchanged:
--- a/core/tests/Drupal/Tests/Core/Cache/BackendChainImplementationUnitTest.php
+++ b/core/tests/Drupal/Tests/Core/Cache/BackendChainImplementationUnitTest.php
@@ -2,6 +2,7 @@
 
 namespace Drupal\Tests\Core\Cache;
 
+use Drupal\Component\Serialization\PhpSerialize;
 use Drupal\Core\Cache\BackendChain;
 use Drupal\Core\Cache\Cache;
 use Drupal\Core\Cache\MemoryBackend;
@@ -45,10 +46,11 @@ class BackendChainImplementationUnitTest extends UnitTestCase {
   protected function setUp() {
     parent::setUp();
 
+    $php_serialize = new PhpSerialize();
     // Set up three memory backends to be used in the chain.
-    $this->firstBackend = new MemoryBackend();
-    $this->secondBackend = new MemoryBackend();
-    $this->thirdBackend = new MemoryBackend();
+    $this->firstBackend = new MemoryBackend($php_serialize);
+    $this->secondBackend = new MemoryBackend($php_serialize);
+    $this->thirdBackend = new MemoryBackend($php_serialize);
 
     // Set an initial fixed dataset for all testing. The next three data
     // collections will test two edge cases (last backend has the data, and
only in patch2:
unchanged:
--- a/core/tests/Drupal/Tests/Core/Cache/ChainedFastBackendTest.php
+++ b/core/tests/Drupal/Tests/Core/Cache/ChainedFastBackendTest.php
@@ -2,6 +2,7 @@
 
 namespace Drupal\Tests\Core\Cache;
 
+use Drupal\Component\Serialization\PhpSerialize;
 use Drupal\Core\Cache\ChainedFastBackend;
 use Drupal\Core\Cache\MemoryBackend;
 use Drupal\Tests\UnitTestCase;
@@ -47,7 +48,7 @@ public function testGetDoesntHitConsistentBackend() {
     $consistent_cache->expects($this->never())
       ->method('getMultiple');
 
-    $fast_cache = new MemoryBackend();
+    $fast_cache = new MemoryBackend(new PhpSerialize());
     $fast_cache->set('foo', 'baz');
 
     $chained_fast_backend = new ChainedFastBackend(