Fixes duplicate listing of third party libraries in credits

tools/licenses.py

 #!/usr/bin/env python
 # 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.
 
 """Utility for checking and processing licensing information in third_party
 directories.
 
 Usage: licenses.py <command>
 
@@ skipping 348 matching lines @@
             # Don't recurse into any subdirs from here.
             dirs[:] = []
             continue
 
         # Don't recurse into paths in ADDITIONAL_PATHS, like we do with regular
         # third_party/foo paths.
         if path in ADDITIONAL_PATHS:
             dirs[:] = []
 
     for dir in ADDITIONAL_PATHS:
-        if dir not in prune_paths:
+        if dir not in prune_paths and dir not in third_party_dirs:

[Paweł Hajdan Jr., 2013/12/18 08:48:12]

nit: Could you make third_party_dirs a set instead?

             third_party_dirs.append(dir)
 
     return third_party_dirs
 
 
 def ScanThirdPartyDirs(root=None):
     """Scan a list of directories and report on any problems we find."""
     if root is None:
       root = os.getcwd()
     third_party_dirs = FindThirdPartyDirs(PRUNE_PATHS, root)
@@ skipping 81 matching lines @@
     elif command == 'credits':
         if not GenerateCredits():
             return 1
     else:
         print __doc__
         return 1
 
 
 if __name__ == '__main__':
   sys.exit(main())