Create CachingRietveld to automatically cache results for presubmit checks.

gcl.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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 simplifies working with groups
 of files.
 """
 
@@ skipping 345 matching lines @@
     gclient_utils.FileWrite(GetChangelistInfoFile(self.name), data)
 
   def Delete(self):
     """Removes the changelist information from disk."""
     os.remove(GetChangelistInfoFile(self.name))
 
   def RpcServer(self):
     if not self._rpc_server:
       if not self.rietveld:
         ErrorExit(CODEREVIEW_SETTINGS_FILE_NOT_FOUND)
-      self._rpc_server = rietveld.Rietveld(self.rietveld, None, None)
+      self._rpc_server = rietveld.CachingRietveld(self.rietveld, None, None)
     return self._rpc_server
 
   def CloseIssue(self):
     """Closes the Rietveld issue for this changelist."""
     # Newer versions of Rietveld require us to pass an XSRF token to POST, so
     # we fetch it from the server.
     xsrf_token = self.SendToRietveld(
         '/xsrf_token',
         extra_headers={'X-Requesting-XSRF-Token': '1'})
 
@@ skipping 1080 matching lines @@
       raise
     print >> sys.stderr, (
         'AppEngine is misbehaving and returned HTTP %d, again. Keep faith '
         'and retry or visit go/isgaeup.\n%s') % (e.code, str(e))
     return 1
 
 
 if __name__ == "__main__":
   fix_encoding.fix_encoding()
   sys.exit(main(sys.argv[1:]))