gcl's caching was effectively disabled for > 1 year. Reenable it.

gcl.py

 #!/usr/bin/python
 # Copyright (c) 2006-2009 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.
 
 """Wrapper script around Rietveld's upload.py that groups files into
 changelists."""
 
 import getpass
 import os
 import random
 import re
 import shutil
 import string
 import subprocess
 import sys
 import tempfile
+import time
 from third_party import upload
 import urllib2
 
 import breakpad
 
 # gcl now depends on gclient.
 from scm import SVN
 import gclient_utils
 
 __version__ = '1.1.3'
@@ skipping 96 matching lines @@
   global FILES_CACHE
   if filename not in FILES_CACHE:
     # Don't try to look up twice.
     FILES_CACHE[filename] = None
     # First we check if we have a cached version.
     try:
       cached_file = os.path.join(GetCacheDir(), filename)
     except gclient_utils.Error:
       return None
     if (not os.path.exists(cached_file) or
-        os.stat(cached_file).st_mtime > max_age):
+        (time.time() - os.stat(cached_file).st_mtime) > max_age):
       dir_info = SVN.CaptureInfo(".")
       repo_root = dir_info["Repository Root"]
       if use_root:
         url_path = repo_root
       else:
         url_path = dir_info["URL"]
       content = ""
       while True:
         # Look in the repository at the current level for the file.
         svn_path = url_path + "/" + filename
@@ skipping 1105 matching lines @@
       return 0
     args =["svn", command]
     root = GetRepositoryRoot()
     args.extend([os.path.join(root, x) for x in change_info.GetFileNames()])
     RunShell(args, True)
   return 0
 
 
 if __name__ == "__main__":
   sys.exit(main())