[3.1.1] Allow injectors to be specified by modules.

- Make method for URI implemented
- Split out checkNeeded in Injector from prepare

git-svn-id: http://htmlpurifier.org/svnroot/htmlpurifier/trunk@1779 48356398-32a2-884e-a903-53898d9a118a

library/HTMLPurifier/AttrDef/URI.php

@@ -18,6 +18,11 @@ class HTMLPurifier_AttrDef_URI extends HTMLPurifier_AttrDef
         $this->embedsResource = (bool) $embeds_resource;
     }
     
+    public function make($string) {
+        $embeds = (bool) $string;
+        return new HTMLPurifier_AttrDef_URI($embeds);
+    }
+    
     public function validate($uri, $config, $context) {
         
         if ($config->get('URI', 'Disable')) return false;