Reland r212020: Move Python setup/tear down logic into Forwarder ...

build/android/pylib/base/test_dispatcher.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.
 
 """Dispatches tests, either sharding or replicating them.
 
 To dispatch, performs the following steps:
 * Create a test collection factory, using the given tests
   - If sharding: test collection factory returns the same shared test collection
     to all test runners
   - If replciating: test collection factory returns a unique test collection to
     each test runner, with the same set of tests in each.
 * Get the list of devices to run on
 * Create test runners
 * Run each test runner in its own thread, pulling tests from the test collection
   generated from the test collection factory until there are no tests left.
 """
 
 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 339 matching lines @@
     tag_results_with_device = False
   else:
     # Generate a unique _TestCollection object for each test runner, but use
     # the same set of tests.
     test_collection_factory = lambda: _TestCollection([_Test(t) for t in tests])
     tag_results_with_device = True
 
   devices = _GetAttachedDevices(wait_for_debugger, test_device)
 
   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, test_collection_factory,
                         num_retries, test_timeout, tag_results_with_device)
   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)