Move drupal_valid_path to PathValidator service

Looks good. All this needs is a change notice and fixing those nitpicks :) :

1. +++ b/core/lib/Drupal/Core/Path/PathValidator.php
   @@ -0,0 +1,116 @@
   +namespace Drupal\Core\Path;
   +use Drupal\Component\Utility\UrlHelper;
   

   newline in between

2. +++ b/core/lib/Drupal/Core/Path/PathValidator.php
   @@ -0,0 +1,116 @@
   + * @todo add class comment.
   

   :)

3. +++ b/core/lib/Drupal/Core/Path/PathValidatorInterface.php
   @@ -0,0 +1,27 @@
   +interface PathValidatorInterface {
   +
   +
   +  /**
   

   Too many newlines here

thanks

+++ b/core/lib/Drupal/Core/Path/PathValidator.php
@@ -0,0 +1,117 @@
+ * Provides a default path validator and access checker.

dont really like the "default" in here, but OK

change notice looks good

I needed to review this because path validation is security related. And this of course is good (or not worse than HEAD) and should could be committed as it.

I moved my concerns to #2302563: Access check Url objects

Committed 291b998 and pushed to 8.x. Thanks!

diff --git a/core/includes/path.inc b/core/includes/path.inc
index ff63a6d..fc7f5fb 100644
--- a/core/includes/path.inc
+++ b/core/includes/path.inc
@@ -5,9 +5,7 @@
  * Functions to handle paths in Drupal.
  */
 
-use Drupal\Component\Utility\UrlHelper;
 use Drupal\Core\ParamConverter\ParamNotConvertedException;
-use Drupal\Core\Routing\RequestHelper;
 use Symfony\Cmf\Component\Routing\RouteObjectInterface;
 
 /**

Fixed on commit.