Issue #3020902 by Berdir, alexpott: PostgresqlDateSql fails to serialize

(cherry picked from commit 60574dd)

Author: alexpott

modules/views/src/Plugin/views/query/PostgresqlDateSql.php

@@ -3,6 +3,7 @@
 namespace Drupal\views\Plugin\views\query;
 
 use Drupal\Core\Database\Connection;
+use Drupal\Core\DependencyInjection\DependencySerializationTrait;
 
 /**
  * PostgreSQL-specific date handling.
@@ -14,6 +15,8 @@
  */
 class PostgresqlDateSql implements DateSqlInterface {
 
+  use DependencySerializationTrait;
+
   /**
    * The database connection.
    *

modules/views/src/Plugin/views/query/SqliteDateSql.php

@@ -3,6 +3,7 @@
 namespace Drupal\views\Plugin\views\query;
 
 use Drupal\Core\Database\Connection;
+use Drupal\Core\DependencyInjection\DependencySerializationTrait;
 
 /**
  * SQLite-specific date handling.
@@ -14,6 +15,8 @@
  */
 class SqliteDateSql implements DateSqlInterface {
 
+  use DependencySerializationTrait;
+
   /**
    * The database connection.
    *

modules/views/tests/src/Kernel/ViewElementTest.php

@@ -82,6 +82,9 @@ public function testViewElementEmbed() {
     $this->assertEqual($render['#embed'], TRUE);
     $this->setRawContent($renderer->renderRoot($render));
 
+    // Ensure that the render array can be serialized.
+    serialize($render);
+
     $xpath = $this->xpath('//div[@class="views-element-container"]');
     $this->assertTrue($xpath, 'The view container has been found in the rendered output.');