Merge branch '2.7' into 2.8

* 2.7:
  [Security] Fix wrong term in UserProviderInterface
  [HttpFoundation] Set meta refresh time to 0 in RedirectResponse content
  [Security] validate empty passwords again
  [DI] Remove irrelevant comment from container
  [TwigBridge] cleaner implementation of the TwigRenderer

Author: fabpot

Form/TwigRenderer.php

@@ -19,23 +19,26 @@
  */
 class TwigRenderer extends FormRenderer implements TwigRendererInterface
 {
-    /**
-     * @var TwigRendererEngineInterface
-     */
-    private $engine;
-
     public function __construct(TwigRendererEngineInterface $engine, $csrfTokenManager = null)
     {
         parent::__construct($engine, $csrfTokenManager);
+    }
 
-        $this->engine = $engine;
+    /**
+     * Returns the engine used by this renderer.
+     *
+     * @return TwigRendererEngineInterface The renderer engine
+     */
+    public function getEngine()
+    {
+        return parent::getEngine();
     }
 
     /**
      * {@inheritdoc}
      */
     public function setEnvironment(Environment $environment)
     {
-        $this->engine->setEnvironment($environment);
+        $this->getEngine()->setEnvironment($environment);
     }
 }