diff --git a/core/lib/Drupal/Core/Installer/InstallerServiceProvider.php b/core/lib/Drupal/Core/Installer/InstallerServiceProvider.php
index 6e93561..37b2181 100644
--- a/core/lib/Drupal/Core/Installer/InstallerServiceProvider.php
+++ b/core/lib/Drupal/Core/Installer/InstallerServiceProvider.php
@@ -39,6 +39,9 @@ public function register(ContainerBuilder $container) {
       ->register('keyvalue', 'Drupal\Core\KeyValueStore\KeyValueMemoryFactory');
     $container
       ->register('keyvalue.expirable', 'Drupal\Core\KeyValueStore\KeyValueNullExpirableFactory');
+    $definition = $container->getDefinition('messenger');
+    $definition->setClass('Drupal\Core\Messenger\StaticMessenger');
+    $definition->setArguments(array('@page_cache_kill_switch'));
 
     // Replace services with no-op implementations.
     $container
diff --git a/core/lib/Drupal/Core/Messenger/StaticMessenger.php b/core/lib/Drupal/Core/Messenger/StaticMessenger.php
new file mode 100644
index 0000000..97b1fc0
--- /dev/null
+++ b/core/lib/Drupal/Core/Messenger/StaticMessenger.php
@@ -0,0 +1,120 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Messenger\StaticMessenger.
+ */
+
+namespace Drupal\Core\Messenger;
+
+use Drupal\Component\Utility\SafeMarkup;
+use Drupal\Core\PageCache\ResponsePolicy\KillSwitch;
+
+/**
+ * Provides a messenger that stores messages for this request only.
+ */
+class StaticMessenger implements MessengerInterface {
+
+  /**
+   * The page caching kill switch.
+   *
+   * @var array[]
+   *   Keys are either self::STATUS, self::WARNING, or self::ERROR. Values are
+   *   arrays of arrays with the following keys:
+   *   - message (string): the message.
+   *   - safe (bool): whether the message is marked as safe markup.
+   */
+  protected $messages = array();
+
+  /**
+   * The page caching kill switch.
+   *
+   * @var \Drupal\Core\PageCache\ResponsePolicy\KillSwitch
+   */
+  protected $pageCacheKillSwitch;
+
+  /**
+   * Constructs a new instance.
+   *
+   * @param \Drupal\Core\PageCache\ResponsePolicy\KillSwitch $page_cache_kill_switch
+   *   The page caching kill switch.
+   */
+  public function __construct(KillSwitch $page_cache_kill_switch) {
+    $this->pageCacheKillSwitch = $page_cache_kill_switch;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function addMessage($message, $type = self::STATUS, $repeat = FALSE) {
+    if ($repeat || !array_key_exists($type, $this->messages) || !in_array($message, $this->messages[$type])) {
+      $this->messages[$type][] = array(
+        'safe' => SafeMarkup::isSafe($message),
+        'message' => $message,
+      );
+      $this->pageCacheKillSwitch->trigger();
+    }
+
+    return $this;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getMessages() {
+    $messages = isset($this->messages) ? $this->messages : array();
+    foreach ($messages as $type => $messages_by_type) {
+      $messages[$type] = $this->processMessages($messages_by_type);
+    }
+
+    return $messages;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getMessagesByType($type) {
+    $messages = isset($this->messages) && isset($this->messages[$type]) ? $this->messages[$type] : array();
+
+    return $this->processMessages($messages);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function deleteMessages() {
+    unset($this->messages);
+
+    return $this;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function deleteMessagesByType($type) {
+    unset($this->messages[$type]);
+
+    return $this;
+  }
+
+  /**
+   * Processes safe markup.
+   *
+   * @param array[]
+   *   An array of arrays with the following keys:
+   *   - message: the message string.
+   *   - safe: a boolean indicating whether the message contains safe markup.
+   *
+   * @return string[]
+   *   The messages.
+   */
+  protected function processMessages(array $messages) {
+    $processed_messages = array();
+    foreach ($messages as $message_data) {
+      $processed_messages[] = $message_data['safe'] ? SafeMarkup::set($message_data['message']) : $message_data['message'];
+    }
+
+    return $processed_messages;
+  }
+
+}
diff --git a/core/tests/Drupal/Tests/Core/Messenger/StaticMessengerTest.php b/core/tests/Drupal/Tests/Core/Messenger/StaticMessengerTest.php
new file mode 100644
index 0000000..6f44600
--- /dev/null
+++ b/core/tests/Drupal/Tests/Core/Messenger/StaticMessengerTest.php
@@ -0,0 +1,97 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\Core\Messenger\MessengerTest.
+ */
+
+namespace Drupal\Tests\Core\Messenger;
+
+use Drupal\Core\Messenger\StaticMessenger;
+use Drupal\Tests\UnitTestCase;
+
+/**
+ * @coversDefaultClass \Drupal\Core\Messenger\StaticMessenger
+ */
+class StaticMessengerTest extends UnitTestCase {
+
+  /**
+   * The messenger under test.
+   *
+   * @var \Drupal\Core\Messenger\StaticMessenger
+   */
+  protected $messenger;
+
+  /**
+   * The page caching kill switch.
+   *
+   * @var \Drupal\Core\PageCache\ResponsePolicy\KillSwitch|\PHPUnit_Framework_MockObject_MockObject
+   */
+  protected $pageCacheKillSwitch;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function getInfo() {
+    return array(
+      'description' => '',
+      'name' => '\Drupal\Core\Messenger\Messenger unit test',
+      'group' => 'Messenger',
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   *
+   * @covers ::__construct
+   */
+  public function setUp() {
+    $this->pageCacheKillSwitch = $this->getMockBuilder('\Drupal\Core\PageCache\ResponsePolicy\KillSwitch')
+      ->disableOriginalConstructor()
+      ->getMock();
+
+    $this->messenger = new StaticMessenger($this->pageCacheKillSwitch);
+  }
+
+  /**
+   * @covers ::addMessage
+   * @covers ::getMessages
+   * @covers ::getMessagesByType
+   * @covers ::deleteMessages
+   * @covers ::deleteMessagesByType
+   */
+  public function testMessenger() {
+    $message_a = $this->randomMachineName();
+    $type_a = $this->randomMachineName();
+    $message_b = $this->randomMachineName();
+    $type_b = $this->randomMachineName();
+
+    $this->pageCacheKillSwitch->expects($this->atLeastOnce())
+      ->method('trigger');
+
+    // Test that if there are no messages, the default is an empty array.
+    $this->assertEquals($this->messenger->getMessages(), array());
+
+    // Test that adding a message returns the messenger and that the message can
+    // be retrieved.
+    $this->assertEquals($this->messenger->addMessage($message_a, $type_a), $this->messenger);
+    $this->messenger->addMessage($message_a, $type_a);
+    $this->messenger->addMessage($message_a, $type_a, TRUE);
+    $this->messenger->addMessage($message_b, $type_b, TRUE);
+    $this->assertEquals($this->messenger->getMessages(), array(
+      $type_a => array($message_a, $message_a, $message_a),
+      $type_b => array($message_b),
+    ));
+
+    // Test deleting messages of a certain type.
+    $this->assertEquals($this->messenger->deleteMessagesByType($type_a), $this->messenger);
+    $this->assertEquals($this->messenger->getMessages(), array(
+      $type_b => array($message_b),
+    ));
+
+    // Test deleting all messages.
+    $this->assertEquals($this->messenger->deleteMessages(), $this->messenger);
+    $this->assertEquals($this->messenger->getMessages(), array());
+  }
+
+}