Android: allow a --single-step for test_runner.py perf.

build/android/pylib/perf/test_runner.py

 # Copyright 2013 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.
 
 """Runs perf tests.
 
 Our buildbot infrastructure requires each slave to run steps serially.
 This is sub-optimal for android, where these steps can run independently on
 multiple connected devices.
 
@@ skipping 123 matching lines @@
     logging.info('%s : %s', test_name, cmd)
     start_time = datetime.datetime.now()
 
     timeout = 1800
     if self._options.no_timeout:
       timeout = None
     full_cmd = cmd
     if self._options.dry_run:
       full_cmd = 'echo %s' % cmd
 
+    logfile = sys.stdout
+    if self._options.single_step:
+      logfile = None
     output, exit_code = pexpect.run(
         full_cmd, cwd=os.path.abspath(constants.DIR_SOURCE_ROOT),
-        withexitstatus=True, logfile=sys.stdout, timeout=timeout,
+        withexitstatus=True, logfile=logfile, timeout=timeout,
         env=os.environ)
     end_time = datetime.datetime.now()
     if exit_code is None:
       exit_code = -1
     logging.info('%s : exit_code=%d in %d secs at %s',
                  test_name, exit_code, (end_time - start_time).seconds,
                  self.device)
     result_type = base_test_result.ResultType.FAIL
     if exit_code == 0:
       result_type = base_test_result.ResultType.PASS
@@ skipping 28 matching lines @@
     Returns:
       A tuple of (TestRunResults, retry).
     """
     output, result_type = self._LaunchPerfTest(test_name)
     results = base_test_result.TestRunResults()
     results.AddResult(base_test_result.BaseTestResult(test_name, result_type))
     retry = None
     if not results.DidRunPass():
       retry = test_name
     return results, retry