Fix detection of GMS proguard.txt files

build/android/play_services/preprocess.py

 #!/usr/bin/env python
 #
 # Copyright 2015 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.
 
 '''Prepares the Google Play services split client libraries before usage by
 Chrome's build system.
 
 We need to preprocess Google Play services before using it in Chrome builds
@@ skipping 202 matching lines @@
       # This file generated by {script}
       gms_proguard_configs = [
       {body}
       ]
       ''')
 
   gni_lines = []
   for client_dir in os.listdir(out_dir):
     proguard_path = os.path.join(
         out_dir, client_dir, 'proguard.txt')
-    if os.path.exists(os.path.dirname(proguard_path)):
+    if os.path.exists(proguard_path):
       rooted_path = os.path.relpath(proguard_path, root_dir)
       gni_lines.append('  "//{}",'.format(rooted_path))
   gni_lines.sort()
 
   gni_text = gni_template.format(
       script=os.path.relpath(sys.argv[0], gni_dir),
       body='\n'.join(gni_lines))
 
   with open(gni_path, 'w') as gni_file:
     gni_file.write(gni_text)
 
 
 def _UpdateVersionInConfig(config, tmp_paths):
   version_xml_path = os.path.join(tmp_paths['imported_clients'],
                                   config.version_xml_path)
   play_services_full_version = utils.GetVersionNumberFromLibraryResources(
       version_xml_path)
   config.UpdateVersionNumber(play_services_full_version)
 
 
 def _ExtractAll(zip_path, out_path):
   with zipfile.ZipFile(zip_path, 'r') as zip_file:
     zip_file.extractall(out_path)
 
 if __name__ == '__main__':
   sys.exit(main())