Docserver: Add commit history and _reset_commit servlet

chrome/common/extensions/docs/server2/availability_finder.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 posixpath
 
 from api_models import GetNodeCategories
 from api_schema_graph import APISchemaGraph
 from branch_utility import BranchUtility, ChannelInfo
 from compiled_file_system import CompiledFileSystem, SingleFile, Unicode
@@ skipping 156 matching lines @@
     and returns it if found.
     '''
     api_filename = _GetAPISchemaFilename(api_name, file_system, version)
     if api_filename is None:
       # No file for the API could be found in the given |file_system|.
       return None
 
     schema_fs = self._CreateAPISchemaFileSystem(file_system)
     api_schemas = schema_fs.GetFromFile(api_filename).Get()
     matching_schemas = [api for api in api_schemas
-                        if api['namespace'] == api_name]
+                        if api and api['namespace'] == api_name]
     # There should only be a single matching schema per file, or zero in the
     # case of no API data being found in _EXTENSION_API.
     assert len(matching_schemas) <= 1
     return matching_schemas or None
 
   def _HasAPISchema(self, api_name, file_system, version):
     '''Whether or not an API schema for |api_name| exists in the given
     |file_system|.
     '''
     filename = _GetAPISchemaFilename(api_name, file_system, version)
@@ skipping 260 matching lines @@
       # Continue looping until there are no longer differences between this
       # version and master.
       return version_stat != master_stat
 
     self._file_system_iterator.Ascending(
         self.GetAPIAvailability(api_name).channel_info,
         update_availability_graph)
 
     self._node_level_object_store.Set(api_name, availability_graph)
     return availability_graph