Docserver: there is only one.

chrome/common/extensions/docs/server2/app_yaml_helper.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 logging
 
 _APP_YAML_CONTAINER = '''
 application: chrome-apps-doc
 version: %s
 runtime: python27
 api_version: 1
 threadsafe: false
 '''
 
 class AppYamlHelper(object):
   '''Parses the app.yaml file, and is able to step back in the host file
   system's revision history to find when it changed to some given version.
   '''
   def __init__(self,
                app_yaml_path,
                file_system_at_head,
                object_store_creator,
-               host_file_system_creator,
-               branch):
+               host_file_system_creator):
     self._app_yaml_path = app_yaml_path
     self._file_system_at_head = file_system_at_head
     self._store = object_store_creator.Create(
         AppYamlHelper,
         category=file_system_at_head.GetIdentity(),
         start_empty=False)
     self._host_file_system_creator = host_file_system_creator
-    self._branch = branch
 
   @staticmethod
   def ExtractVersion(app_yaml, key='version'):
     '''Extracts the 'version' key from the contents of an app.yaml file.
     Allow overriding the key to parse e.g. the cron file ('target').
     '''
     # We could properly parse this using a yaml library but Python doesn't have
     # one built in so whatevs.
     key_colon = '%s:' % key
     versions = [line.strip()[len(key_colon):].strip()
@@ skipping 70 matching lines @@
     found = None
     next_file_system = self._file_system_at_head
 
     while has_greater_app_version(next_file_system):
       found = get_app_yaml_revision(next_file_system)
       # Back up a revision then find when app.yaml was last updated before then.
       if found == 0:
         logging.warning('All revisions are greater than %s' % app_version)
         return 0
       next_file_system = self._host_file_system_creator.Create(
-          self._branch,
           revision=found - 1)
 
     if found is None:
       raise ValueError('All revisions are less than %s' % app_version)
     return found