Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.1101
diff -u -r1.1101 common.inc
--- includes/common.inc	7 Feb 2010 05:12:34 -0000	1.1101
+++ includes/common.inc	9 Feb 2010 22:46:22 -0000
@@ -3898,7 +3898,7 @@
           if ($item['defer']) {
             $js_element['#attributes']['defer'] = 'defer';
           }
-          $js_element['#attributes']['src'] = file_create_url($item['data']) . ($item['cache'] ? $query_string : '?' . REQUEST_TIME);
+          $js_element['#attributes']['src'] = file_create_url($item['data'], FALSE) . ($item['cache'] ? $query_string : '?' . REQUEST_TIME);
           $no_preprocess .= theme('html_tag', array('element' => $js_element));
         }
         else {
@@ -3923,7 +3923,7 @@
     // Prefix filename to prevent blocking by firewalls which reject files
     // starting with "ad*".
     $filename = 'js_' . md5(serialize($files) . $query_string) . '.js';
-    $preprocess_file = file_create_url(drupal_build_js_cache($files, $filename));
+    $preprocess_file = file_create_url(drupal_build_js_cache($files, $filename), FALSE);
     $js_element = $element;
     $js_element['#attributes']['src'] = $preprocess_file;
     $preprocessed .= theme('html_tag', array('element' => $js_element)) . "\n";
Index: includes/file.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/file.inc,v
retrieving revision 1.205
diff -u -r1.205 file.inc
--- includes/file.inc	1 Feb 2010 19:07:07 -0000	1.205
+++ includes/file.inc	9 Feb 2010 22:46:23 -0000
@@ -329,16 +329,20 @@
  * @param $uri
  *   The URI to a file for which we need an external URL, or the path to a
  *   shipped file.
+ * @param $alter
+ *   FALSE indicates that modules cannot alter the URI. The default is TRUE.
  * @return
  *   A string containing a URL that may be used to access the file.
  *   If the provided string already contains a preceding 'http', nothing is done
  *   and the same string is returned. If a valid stream wrapper could not be
  *   found to generate an external URL, then FALSE will be returned.
  */
-function file_create_url($uri) {
+function file_create_url($uri, $alter = TRUE) {
   // Allow the URI to be altered, e.g. to serve a file from a CDN or static
   // file server.
-  drupal_alter('file_url', $uri);
+  if ($alter) {
+    drupal_alter('file_url', $uri);
+  }
 
   $scheme = file_uri_scheme($uri);