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

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

Index: chrome/common/extensions/docs/server2/github_file_system.py
diff --git a/chrome/common/extensions/docs/server2/github_file_system.py b/chrome/common/extensions/docs/server2/github_file_system.py
index ccb51c44185f7f9b428f70eeadb145e063fc0d69..0422c6ef6ca9b44864b9c37882034c8d032fc275 100644
--- a/chrome/common/extensions/docs/server2/github_file_system.py
+++ b/chrome/common/extensions/docs/server2/github_file_system.py
@@ -7,7 +7,7 @@ import os
 
 import appengine_blobstore as blobstore
 import appengine_memcache as memcache
-import file_system
+from file_system import FileSystem, StatInfo
 from io import BytesIO
 from future import Future
 from zipfile import ZipFile
@@ -33,7 +33,7 @@ class _AsyncFetchFutureZip(object):
                            blobstore.BLOBSTORE_GITHUB)
     return ZipFile(BytesIO(blob))
 
-class GithubFileSystem(file_system.FileSystem):
+class GithubFileSystem(FileSystem):
   """FileSystem implementation which fetches resources from github.
   """
   def __init__(self, fetcher, memcache, blobstore):
@@ -84,8 +84,8 @@ class GithubFileSystem(file_system.FileSystem):
   def Stat(self, path):
     version = self._memcache.Get(path, memcache.MEMCACHE_GITHUB_STAT)
     if version is not None:
-      return self.StatInfo(version)
+      return StatInfo(version)
     version = json.loads(
         self._fetcher.Fetch('commits/HEAD').content)['commit']['tree']['sha']
     self._memcache.Set(path, version, memcache.MEMCACHE_GITHUB_STAT)
-    return self.StatInfo(version)
+    return StatInfo(version)