More changes to support hermetic Xcode toolchain in GN.

chrome/tools/build/mac/copy_keystone_framework.py

Index: chrome/tools/build/mac/copy_keystone_framework.py
diff --git a/chrome/tools/build/mac/copy_keystone_framework.py b/chrome/tools/build/mac/copy_keystone_framework.py
index b43893bf8aa7847375a04c421d849f2dde69a4d3..513fdc9118a1144d81839b8f9d5ad25e408f295d 100644
--- a/chrome/tools/build/mac/copy_keystone_framework.py
+++ b/chrome/tools/build/mac/copy_keystone_framework.py
@@ -2,21 +2,25 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import os
 import os.path
 import shutil
 import subprocess
 import sys
 
 # Usage: python copy_keystone_framework.py /path/to/input /path/to/output
+#        [DEVELOPER_DIR]
 #
 # This script copies the KeystoneRegistration.framework, removing its
 # versioned directory structure, thinning it to just x86_64, and deleting
 # the Headers directory.
 
 def Main(args):
-  if len(args) != 3:
+  if len(args) != 3 and len(args) != 4:
     print >> sys.stderr, '%s: /path/to/input /path/to/output' % (args[0],)
     return 1
+  if len(args) == 4:
+    os.environ['DEVELOPER_DIR'] = args[3]
 
   # Delete any old copies of the framework.
   output_path = os.path.join(args[2], 'KeystoneRegistration.framework')