Pass path to gn binary to cronet_licenses.py when building for iOS.

components/cronet/tools/cronet_licenses.py

 #!/usr/bin/python
 # Copyright 2014 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.
 
 """Generates the contents of an Cronet LICENSE file for the third-party code.
 
 It makes use of src/tools/licenses.py and the README.chromium files on which
 it depends. Based on android_webview/tools/webview_licenses.py.
 """
@@ skipping 46 matching lines @@
     content.append('-' * 20)
     content.append(directory.split("/")[-1])
     content.append('-' * 20)
     license_file = metadata['License File']
     if license_file and license_file != licenses.NOT_SHIPPED:
       content.append(_ReadFile(license_file))
 
   return '\n'.join(content)
 
 
-def FindThirdPartyDeps(gn_out_dir):
+def FindThirdPartyDeps(gn_path, gn_out_dir):
   # Generate gn project in temp directory and use it to find dependencies.
   # Current gn directory cannot ba used because gn doesn't allow recursive
   # invocations due to potential side effects.
   try:
     tmp_dir = tempfile.mkdtemp(dir = gn_out_dir)
     shutil.copy(gn_out_dir + "/args.gn", tmp_dir)
-    subprocess.check_output(["gn", "gen", tmp_dir])
-    gn_deps = subprocess.check_output(["gn", "desc", tmp_dir, \
+    subprocess.check_output([gn_path, "gen", tmp_dir])
+    gn_deps = subprocess.check_output([gn_path, "desc", tmp_dir,
                                     "//net", "deps", "--as=buildfile", "--all"])
   finally:
     if os.path.exists(tmp_dir):
       shutil.rmtree(tmp_dir)
 
   third_party_deps = []
   for build_dep in gn_deps.split():
     if ("third_party" in build_dep and build_dep.endswith("/BUILD.gn")):
       third_party_deps.append(build_dep.replace("/BUILD.gn", ""))
   third_party_deps.sort()
   return third_party_deps
 
 
 def main():
   class FormatterWithNewLines(optparse.IndentedHelpFormatter):
     def format_description(self, description):
       paras = description.split('\n')
       formatted_paras = [textwrap.fill(para, self.width) for para in paras]
       return '\n'.join(formatted_paras) + '\n'
 
   parser = optparse.OptionParser(formatter=FormatterWithNewLines(),
                                  usage='%prog command [options]')
   parser.add_option('--gn', help='Use gn deps to find third party dependencies',
                     action='store_true')
+  parser.add_option('--gn-path', default='gn',
+                    help='Path to gn executable (default: %(default)s)')
   parser.description = (__doc__ +
                        '\nCommands:\n' \
                        '  license [filename]\n' \
                        '    Generate Cronet LICENSE to filename or stdout.\n')
-  (_, args) = parser.parse_args()
+  (flags, args) = parser.parse_args()
+  print flags
 
-  if _.gn:
+  if flags.gn:
     global third_party_dirs
-    third_party_dirs = FindThirdPartyDeps(os.getcwd())
+    third_party_dirs = FindThirdPartyDeps(flags.gn_path, os.getcwd())
 
   if not args:
     parser.print_help()
     return 1
 
   if args[0] == 'license':
     if len(args) > 1:
       f = open(args[1], "w")
       try:
         f.write(GenerateLicense())
       finally:
         f.close()
     else:
       print GenerateLicense()
     return 0
 
   parser.print_help()
   return 1
 
 
 if __name__ == '__main__':
   sys.exit(main())