Disable failing perf unit tests on chromeos.

tools/perf/profile_creators/cookie_profile_extender_unittest.py

 # Copyright 2015 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.
 import os
-import sqlite3
 import tempfile
 import unittest
 
+try:
+  import sqlite3  # Not present on ChromeOS.
+except ImportError:
+  pass
+
+
+from telemetry import decorators
 from profile_creators.cookie_profile_extender import CookieProfileExtender
 
 
 # Testing private method.
 # pylint: disable=protected-access
 class CookieProfileExtenderTest(unittest.TestCase):
   def _CreateCookieTable(self, path):
     connection = sqlite3.connect(path)
     cursor = connection.cursor()
     cursor.execute("CREATE TABLE cookies (url text)")
     connection.commit()
     connection.close()
 
   def _AddCookiesToTable(self, path, count):
     connection = sqlite3.connect(path)
     cursor = connection.cursor()
     for i in range(count):
       cursor.execute("INSERT INTO cookies VALUES ('%s')" % i)
     connection.commit()
     connection.close()
 
+  @decorators.Disabled('chromeos')  # crbug.com/483212
   def testCookieCount(self):
     # Neither tempfile.TemporaryFile() nor tempfile.NamedTemporaryFile() work
     # well here. The former doesn't work at all, since it doesn't gaurantee a
     # file-system visible path. The latter doesn't work well, since the
     # returned file cannot be opened a second time on Windows. The returned
     # file would have to be closed, and the method would need to be called with
     # Delete=False, which makes its functionality no simpler than
     # tempfile.mkstemp().
     handle, path = tempfile.mkstemp()
     try:
       os.close(handle)
 
       self._CreateCookieTable(path)
       self.assertEquals(CookieProfileExtender._CookieCountInDB(path), 0)
 
       self._AddCookiesToTable(path, 100)
       self.assertEquals(CookieProfileExtender._CookieCountInDB(path), 100)
     finally:
       os.remove(path)