use "/" instead of path.sep in owners glob check

owners.py

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """A database of OWNERS files.
 
 OWNERS files indicate who is allowed to approve changes in a specific directory
 (or who is allowed to make changes without needing approval of another OWNER).
 Note that all changes must still be reviewed by someone familiar with the code,
 so you may need approval from both an OWNER and a reviewer in many cases.
@@ skipping 206 matching lines @@
         continue
       if line == 'set noparent':
         self.stop_looking.add(dirpath)
         continue
 
       m = re.match("per-file (.+)=(.+)", line)
       if m:
         glob_string = m.group(1)
         directive = m.group(2)
         full_glob_string = self.os_path.join(self.root, dirpath, glob_string)
-        if self.os_path.sep in glob_string:
+        if '/' in glob_string or '\\' in glob_string:
           raise SyntaxErrorInOwnersFile(owners_path, lineno,
-              'per-file globs cannot span directories: "%s"' % line)
+              'per-file globs cannot span directories or use escapes: "%s"' %
+              line)
         baselines = self.glob(full_glob_string)
         for baseline in (self.os_path.relpath(b, self.root) for b in baselines):
           self._add_entry(baseline, directive, "per-file line",
                           owners_path, lineno)
         continue
 
       if line.startswith('set '):
         raise SyntaxErrorInOwnersFile(owners_path, lineno,
             'unknown option: "%s"' % line[4:].strip())
 
@@ skipping 59 matching lines @@
         break
 
       final_owners.add(max_owner)
 
       # Remove all directories owned by the current owner from the remaining
       # list.
       for dirname in owned_dirs[max_owner]:
         dirs.discard(dirname)
 
     return final_owners