Add force_sync option to chromite.checkout.

scripts/slave/recipe_modules/chromite/api.py

 # Copyright 2013 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 cgi
 import re
 
 from recipe_engine import recipe_api
 
 
@@ skipping 185 matching lines @@
     """
     cfg = self.m.gclient.make_config()
     soln = cfg.solutions.add()
     soln.name = 'chromite'
     soln.url = self.chromite_url
     # Set the revision using 'bot_update' remote branch:revision notation.
     # Omitting the revision uses HEAD.
     soln.revision = '%s:' % (self.c.chromite_branch,)
     return cfg
 
-  def checkout(self, manifest_url=None, repo_url=None):
+  def checkout(self, manifest_url=None, repo_url=None, force_sync=False):
     manifest_url = manifest_url or self.manifest_url
     repo_url = repo_url or self.repo_url
 
     self.m.repo.init(manifest_url, '--repo-url', repo_url)
-    self.m.repo.sync()
+    args = []
+    if force_sync:
+      args.append('--force-sync')
+    self.m.repo.sync(*args)
 
   @property
   def using_old_chromite_layout(self):
     """Returns (bool): True if we're using old Chromite checkout layout.
     """
     return self.c.chromite_branch in self.c.old_chromite_branches
 
   def cbuildbot(self, name, config, args=None, **kwargs):
     """Runs the cbuildbot command defined by the arguments.
 
@@ skipping 207 matching lines @@
       cbb_args.extend(['--master-build-id', self.c.cbb.build_id])
 
     # Add custom args, if there are any.
     cbb_args.extend(self.c.cbb.extra_args)
 
     # Run cbuildbot.
     return self.cbuildbot(str('cbuildbot [%s]' % (self.c.cbb.config,)),
                           self.c.cbb.config,
                           args=cbb_args,
                           cwd=self.m.path['slave_build'])