bug #27359 [HttpFoundation] Fix perf issue during MimeTypeGuesser int…

…ialization (nicolas-grekas)

This PR was merged into the 2.7 branch.

Discussion
----------

[HttpFoundation] Fix perf issue during MimeTypeGuesser intialization

| Q             | A
| ------------- | ---
| Branch?       | 2.7
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #27307
| License       | MIT
| Doc PR        | -

introduced in #26886

![image](https://user-images.githubusercontent.com/243674/40451947-918f5358-5ee0-11e8-9f1a-cf707bf3cefa.png)

Commits
-------

f8e7a18 [HttpFoundation] Fix perf issue during MimeTypeGuesser intialization

src/Symfony/Component/HttpFoundation/File/MimeType/MimeTypeGuesser.php

@@ -80,13 +80,8 @@ public static function reset()
      */
     private function __construct()
     {
-        if (FileBinaryMimeTypeGuesser::isSupported()) {
-            $this->register(new FileBinaryMimeTypeGuesser());
-        }
-
-        if (FileinfoMimeTypeGuesser::isSupported()) {
-            $this->register(new FileinfoMimeTypeGuesser());
-        }
+        $this->register(new FileBinaryMimeTypeGuesser());
+        $this->register(new FileinfoMimeTypeGuesser());
     }
 
     /**
@@ -125,18 +120,14 @@ public function guess($path)
             throw new AccessDeniedException($path);
         }
 
-        if (!$this->guessers) {
-            $msg = 'Unable to guess the mime type as no guessers are available';
-            if (!FileinfoMimeTypeGuesser::isSupported()) {
-                $msg .= ' (Did you enable the php_fileinfo extension?)';
-            }
-            throw new \LogicException($msg);
-        }
-
         foreach ($this->guessers as $guesser) {
             if (null !== $mimeType = $guesser->guess($path)) {
                 return $mimeType;
             }
         }
+
+        if (2 === \count($this->guessers) && !FileBinaryMimeTypeGuesser::isSupported() && !FileinfoMimeTypeGuesser::isSupported()) {
+            throw new \LogicException('Unable to guess the mime type as no guessers are available (Did you enable the php_fileinfo extension?)');
+        }
     }
 }