feature #18371 [FrameworkBundle] integrate the Cache component (xabbuh, nicolas-grekas)

This PR was merged into the 3.1-dev branch.

Discussion
----------

[FrameworkBundle] integrate the Cache component

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #17537
| License       | MIT
| Doc PR        | -

Last commit is the diff with #17868.

Commits
-------

4152634 [FrameworkBundle] Add default pool & system adapter
714b916 [FrameworkBundle] Add & use Psr6CacheClearer
4740c5c [FrameworkBundle] use abstract cache.pool decoration and aliases
92b1a20 [FrameworkBundle] Fix and add tests for cache pool wiring
e44bfdc [FrameworkBundle] Add cache-pool tag and wiring
281eafa [FrameworkBundle] Integrate the Cache component
bc51fde [Cache] Normalize constructor arguments order

Author: fabpot

CacheClearer/Psr6CacheClearer.php

@@ -0,0 +1,37 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpKernel\CacheClearer;
+
+use Psr\Cache\CacheItemPoolInterface;
+
+/**
+ * @author Nicolas Grekas <[email protected]>
+ */
+class Psr6CacheClearer implements CacheClearerInterface
+{
+    private $pools = array();
+
+    public function addPool(CacheItemPoolInterface $pool)
+    {
+        $this->pools[] = $pool;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function clear($cacheDir)
+    {
+        foreach ($this->pools as $pool) {
+            $pool->clear();
+        }
+    }
+}