Add CIPD support for bot assets

infra/bots/utils.py

 #!/usr/bin/env python
 #
 # Copyright 2016 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 
 import datetime
 import errno
 import os
 import shutil
 import sys
 import subprocess
 import tempfile
 import time
 import uuid
 
 
 GCLIENT = 'gclient.bat' if sys.platform == 'win32' else 'gclient'
 GIT = 'git.bat' if sys.platform == 'win32' else 'git'
+WHICH = 'where' if sys.platform == 'win32' else 'which'
 
 
 class print_timings(object):
   def __init__(self):
     self._start = None
 
   def __enter__(self):
     self._start = datetime.datetime.utcnow()
     print 'Task started at %s GMT' % str(self._start)
 
@@ skipping 159 matching lines @@
     # For POSIX:  making the directory writable guarantees removability.
     # Windows will ignore the non-read-only bits in the chmod value.
     os.chmod(root, 0770)
     for name in files:
       remove_with_retry(os.remove, os.path.join(root, name))
     for name in dirs:
       remove_with_retry(lambda p: shutil.rmtree(p, onerror=RmTreeOnError),
                         os.path.join(root, name))
 
   remove_with_retry(os.rmdir, file_path)