[Sync] Add support for performing a GetKey on startup.

net/tools/testserver/chromiumsync_test.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.
 
 """Tests exercising chromiumsync and SyncDataModel."""
 
 import pickle
 import unittest
 
@@ skipping 582 matching lines @@
         version2)
 
     # Ensure getting from timestamp 0 includes the folder.
     version, changes, remaining = (
         self.GetChangesFromTimestamp([chromiumsync.BOOKMARK], 0))
     self.assertEqual(
         self.ExpectedPermanentItemCount(chromiumsync.BOOKMARK),
         len(changes))
     self.assertEqual(version2, version)
 
+  def testGetKey(self):
+    key1 = self.model.GetKey()
+    key2 = self.model.GetKey()
+    self.assertTrue(len(key1) > 0)
+    self.assertEqual(key1, key2)
+
 
 if __name__ == '__main__':
   unittest.main()