Reduce flakiness of browser tests.

frog/scripts/buildbot_annotated_steps.py

 #!/usr/bin/python
 
 # Copyright (c) 2011 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.
 
 """Dart frog buildbot steps
 
 Runs tests for the frog compiler (running on the vm or the self-hosting version)
 """
@@ skipping 32 matching lines @@
 
 
 def TestStep(name, mode, system, component, targets, flags):
   print '@@@BUILD_STEP %s tests: %s %s@@@' % (name, component, flags)
   sys.stdout.flush()
   if (component == 'frogium' or component == 'webdriver') and system == 'linux':
     cmd = ['xvfb-run', '-a']
   else:
     cmd = []
 
-  num_tasks = 8
-  if system == 'windows':
-    # TODO(efortuna): This is a temporary measure because webdriver isn't
-    # threadsafe(!), and the results seem to be most obvious/problematic on 
-    # Windows.
-    num_tasks = 1
-  
   cmd = (cmd
       + [sys.executable,
           os.path.join('..', 'tools', 'test_wrapper.py'),
           '--mode=' + mode,
           '--component=' + component,
           '--time',
           '--report',
-          '-j%d' % num_tasks,
           '--progress=buildbot',
           '-v']
       + targets)
   if flags:
     cmd.extend(flags)
 
   exit_code = subprocess.call(cmd, env=NO_COLOR_ENV)
   if exit_code != 0:
     print '@@@STEP_FAILURE@@@'
   return exit_code
@@ skipping 95 matching lines @@
 
   status = TestFrog(arch, mode, system, ['--checked'])
   if status != 0:
     print '@@@STEP_FAILURE@@@'
 
   return status
 
 
 if __name__ == '__main__':
   sys.exit(main())