Correct iOS GN hermetic support.

build/config/ios/codesign.py

 # Copyright 2016 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.
 
 import argparse
 import datetime
 import fnmatch
 import glob
 import os
 import plistlib
@@ skipping 396 matching lines @@
     info_plist = LoadPlistFile(args.info_plist)
     bundle_identifier = info_plist['CFBundleIdentifier']
     provisioning_profile = FindProvisioningProfile(bundle_identifier, False)
     entitlements = GenerateEntitlements(
         args.entitlements_path, provisioning_profile, bundle_identifier)
     entitlements.WriteTo(args.path)
 
 
 def Main():
   parser = argparse.ArgumentParser('codesign iOS bundles')
+  parser.add_argument('--developer_dir', required=False,
+                      help='Path to Xcode.')
   subparsers = parser.add_subparsers()
 
   actions = [
       CodeSignBundleAction,
       CodeSignFileAction,
       GenerateEntitlementsAction,
   ]
 
   for action in actions:
     action.Register(subparsers)
 
   args = parser.parse_args()
+  if args.developer_dir:
+    os.environ['DEVELOPER_DIR'] = args.developer_dir
   args.func(args)
 
 
 if __name__ == '__main__':
   sys.exit(Main())