Docs: Memoize the FeaturesBundles that are created by AvailabilityFinder to

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.
 
 from collections import Mapping
 import posixpath
 
 from api_schema_graph import APISchemaGraph
 from branch_utility import BranchUtility
 from extensions_paths import API_PATHS, JSON_TEMPLATES
 from features_bundle import FeaturesBundle
 import features_utility
 from file_system import FileNotFoundError
+from third_party.json_schema_compiler.memoize import memoize
 from third_party.json_schema_compiler.model import UnixName
 
 
 _EXTENSION_API = 'extension_api.json'
 
 # The version where api_features.json is first available.
 _API_FEATURES_MIN_VERSION = 28
 # The version where permission_ and manifest_features.json are available and
 # presented in the current format.
 _ORIGINAL_FEATURES_MIN_VERSION = 20
@@ skipping 146 matching lines @@
       # If an API is not represented in any of the _features files, but exists
       # in the filesystem, then assume it is available in this version.
       # The chrome.windows API is an example of this.
       available_channel = channel_info.channel
     # If the channel we're checking is the same as or newer than the
     # |available_channel| then the API is available at this channel.
     newest = BranchUtility.NewestChannel((available_channel,
                                           channel_info.channel))
     return available_channel is not None and newest == channel_info.channel
 
+  @memoize
   def _CreateFeaturesBundle(self, file_system):
     return FeaturesBundle(file_system,
                           self._compiled_fs_factory,
                           self._object_store_creator)
 
   def _GetChannelFromApiFeatures(self, api_name, features_bundle):
     return _GetChannelFromFeatures(api_name, features_bundle.GetAPIFeatures())
 
   def _GetChannelFromManifestFeatures(self, api_name, features_bundle):
     # _manifest_features.json uses unix_style API names.
@@ skipping 92 matching lines @@
 
       # Continue looping until there are no longer differences between this
       # version and trunk.
       return version_stat != trunk_stat
 
     self._file_system_iterator.Ascending(self.GetApiAvailability(api_name),
                                          update_availability_graph)
 
     self._node_level_object_store.Set(api_name, availability_graph)
     return availability_graph