Fix for flakiness in pyauto automation hook WaitForDownloadsToComplete.

chrome/test/pyautolib/download_info.py

 #!/usr/bin/python
 
 # Copyright (c) 2010 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.
 
 """DownloadInfo: python representation for downloads visible to Chrome.
 
 Obtain one of these from PyUITestSuite::GetDownloadsInfo() call.
 
 class MyDownloadsTest(pyauto.PyUITest):
   def testDownload(self):
-    self.NavigateToURL('http://my.url/package.zip')
-    self.WaitForDownloadsToComplete()
+    pre_download_ids = [x['id'] for x in self.GetDownloadsInfo().Downloads()]
+    self.DownloadAndWaitForStart('http://my.url/package.zip')
+    self.WaitForAllDownloadsToComplete(pre_download_ids)
     info = self.GetDownloadsInfo()
     print info.Downloads()
     self.assertEqual(info.Downloads()[0]['file_name'], 'packge.zip')
 
 See more tests in chrome/test/functional/downloads.py.
 """
 
 import os
 import simplejson as json
 import sys
@@ skipping 47 matching lines @@
     """
     return [x for x in self.Downloads() if x['state'] == 'IN_PROGRESS']
 
   def DownloadsComplete(self):
     """Info about all downloads that have completed.
 
     Returns:
       [downloaditem1, downloaditem2, ...]
     """
     return [x for x in self.Downloads() if x['state'] == 'COMPLETE']