Re-re-land gclient deletion of mismatching checkouts again

gclient_utils.py

 # Copyright (c) 2012 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.
 
 """Generic utils."""
 
 import codecs
 import logging
 import os
 import pipes
 import Queue
 import re
+import socket
 import stat
 import subprocess
 import sys
 import tempfile
 import threading
 import time
 import urlparse
 
 import subprocess2
 
 
 RETRY_MAX = 3
 RETRY_INITIAL_SLEEP = 0.5
 
 
+def enable_deletion_of_conflicting_checkouts():
+  """Determines whether to enable new checkout deletion behavior.
+
+  Initially, enables the experimental functionality on a small set of
+  bots.
+  """
+  # TODO(borenet): Remove this hack as soon as we've verified that it
+  # doesn't cause the bots to break.
+  if not os.environ.get('CHROME_HEADLESS'):
+    return False
+  return socket.gethostname() in ('vm859-m1', 'BUILD1-M1',
+                                  'vm630-m1.golo.chromium.org')
+
+
 class Error(Exception):
   """gclient exception class."""
   def __init__(self, msg, *args, **kwargs):
     index = getattr(threading.currentThread(), 'index', 0)
     if index:
       msg = '\n'.join('%d> %s' % (index, l) for l in msg.splitlines())
     super(Error, self).__init__(msg, *args, **kwargs)
 
 
 def SplitUrlRevision(url):
@@ skipping 912 matching lines @@
 
   Python on OSX 10.6 raises a NotImplementedError exception.
   """
   try:
     import multiprocessing
     return multiprocessing.cpu_count()
   except:  # pylint: disable=W0702
     # Mac OS 10.6 only
     # pylint: disable=E1101
     return int(os.sysconf('SC_NPROCESSORS_ONLN'))