Enable retries for failed xctests

ios/build/bots/scripts/test_runner.py

 # Copyright 2016 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.
 
 """Test runners for iOS."""
 
 import argparse
 import collections
 import errno
 import os
@@ skipping 333 matching lines @@
           passed.extend(result.passed_tests)
           failed.update(result.failed_tests)
           flaked.update(result.flaked_tests)
       except OSError as e:
         if e.errno == errno.E2BIG:
           print 'Too many test cases to resume.'
           print
         else:
           raise
 
-      # Retry failed test cases. Currently, XCTests don't support retries
-      # because there are no arguments to select specific tests to run.
-      if self.retries and failed and not self.xctest_path:
+      # Retry failed test cases.
+      if self.retries and failed:
         print '%s tests failed and will be retried.' % len(failed)
         print
         for i in xrange(self.retries):
           for test in failed.keys():
             print 'Retry #%s for %s.' % (i + 1, test)
             print
             result = self._run(self.get_launch_command(test_filter=[test]))
             # If the test passed on retry, consider it flake instead of failure.
             if test in result.passed_tests:
               flaked[test] = failed.pop(test)
@@ skipping 419 matching lines @@
     """
     env = super(DeviceTestRunner, self).get_launch_env()
     if self.xctest_path:
       env['NSUnbufferedIO'] = 'YES'
       # e.g. ios_web_shell_egtests
       env['APP_TARGET_NAME'] = os.path.splitext(
           os.path.basename(self.app_path))[0]
       # e.g. ios_web_shell_egtests_module
       env['TEST_TARGET_NAME'] = env['APP_TARGET_NAME'] + '_module'
     return env