Make Request::isFromTrustedProxy() public.

Also add documentation so we know what it can be used for.

Author: Peter Bex

src/Symfony/Component/HttpFoundation/Request.php

@@ -1931,7 +1931,15 @@ private static function createRequestFromFactory(array $query = array(), array $
         return new static($query, $request, $attributes, $cookies, $files, $server, $content);
     }
 
-    private function isFromTrustedProxy()
+    /**
+     * Indicates whether this request originated from a trusted proxy.
+     *
+     * This can be useful to determine whether or not to trust the
+     * contents of a proxy-specific header.
+     *
+     * @return bool true if the request came from a trusted proxy, false otherwise
+     */
+    public function isFromTrustedProxy()
     {
         return self::$trustedProxies && IpUtils::checkIp($this->server->get('REMOTE_ADDR'), self::$trustedProxies);
     }