Add argument use_poll=True to asyncore.loop() calls in perf_snapshot.py.

chrome/test/functional/perf_endure.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.
 
 """Performance tests for Chrome Endure (long-running perf tests on Chrome).
 """
 
 import logging
 import os
@@ skipping 55 matching lines @@
     """
     info = self.GetProcessInfo()
     tab_proc_info = []
     for browser_info in info['browsers']:
       for proc_info in browser_info['processes']:
         if (proc_info['child_process_type'] == 'Tab' and
             [x for x in proc_info['titles'] if tab_title_substring in x]):
           tab_proc_info.append(proc_info)
     self.assertEqual(len(tab_proc_info), 1,
                      msg='Expected to find 1 %s tab process, but found %d '
-                         'instead.' % (tab_title_substring, len(tab_proc_info)))
+                         'instead.\nCurrent process info:\n%s.' % (
+                         tab_title_substring, len(tab_proc_info),
+                         self.pformat(info)))
     tab_proc_info = tab_proc_info[0]
     return {
       'private_mem': tab_proc_info['working_set_mem']['priv']
     }
 
   def _GetPerformanceStats(self, webapp_name, tab_title_substring):
     """Gets performance statistics and outputs the results.
 
     Args:
       webapp_name: A string name for the webapp being tested.  Should not
@@ skipping 349 matching lines @@
       if not self._WaitForElementByXpath(
           driver, wait, '//div[text()="Acquaintances"]'):
         num_errors += 1
       time.sleep(1)
 
     self._GetPerformanceStats(self._webapp_name, self._tab_title_substring)
 
 
 if __name__ == '__main__':
   pyauto_functional.Main()