Extension docs server: many changes to bring down the latency of the server,

chrome/common/extensions/docs/server2/file_system_cache.py

Index: chrome/common/extensions/docs/server2/file_system_cache.py
diff --git a/chrome/common/extensions/docs/server2/file_system_cache.py b/chrome/common/extensions/docs/server2/file_system_cache.py
index a38df42f3144f38d976663726606525c7d513dc6..53522e2d81d583c8286f09d7100d33d7a2393900 100644
--- a/chrome/common/extensions/docs/server2/file_system_cache.py
+++ b/chrome/common/extensions/docs/server2/file_system_cache.py
@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 import os
+from request_scoped_fs_cache import RequestScopedFsCache
 
 class FileSystemCache(object):
   """This class caches FileSystem data that has been processed.
@@ -26,6 +27,9 @@ class FileSystemCache(object):
     self._populate_function = populate_function
     self._cache = {}
 
+  def ScopeToRequest(self):
+    return RequestScopedFsCache(self)
+
   def _RecursiveList(self, files):
     all_files = files[:]
     dirs = {}