Move Python setup/tear down logic into Forwarder itself.

build/android/pylib/base/shard.py

 # Copyright (c) 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.
 
 """Implements test sharding logic."""
 
 import logging
 import threading
 
 from pylib import android_commands
 from pylib import constants
-from pylib import forwarder
 from pylib.utils import reraiser_thread
 from pylib.utils import watchdog_timer
 
 import base_test_result
 
 
 DEFAULT_TIMEOUT = 7 * 60  # seven minutes
 
 
 class _ThreadSafeCounter(object):
@@ skipping 263 matching lines @@
     num_retries: number of retries for a test.
 
   Returns:
     A tuple of (base_test_result.TestRunResults object, exit code).
   """
   if not tests:
     logging.error('No tests to run.')
     return (base_test_result.TestRunResults(), constants.ERROR_EXIT_CODE)
 
   logging.info('Will run %d tests: %s', len(tests), str(tests))
-  forwarder.Forwarder.KillHost(build_type)
   runners = _CreateRunners(runner_factory, devices, setup_timeout)
   try:
     return _RunAllTests(runners, tests, num_retries, test_timeout)
   finally:
     try:
       _TearDownRunners(runners, setup_timeout)
     except android_commands.errors.DeviceUnresponsiveError as e:
       logging.warning('Device unresponsive during TearDown: [%s]', e)
-    finally:
-      forwarder.Forwarder.KillHost(build_type)