Enable presubmit pylint in build/android.

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.
 
 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.
 * Create a test runner for each device.
 * Run each test runner in its own thread, grabbing tests from the test
   collection until there are no tests left.
 """
 
 import logging
 import threading
 
 from pylib import android_commands
 from pylib import constants
+from pylib.base import base_test_result
 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):
   """A threadsafe counter."""
 
   def __init__(self):
     self._lock = threading.Lock()
     self._value = 0
@@ skipping 24 matching lines @@
     self.tries = tries
 
 
 class _TestCollection(object):
   """A threadsafe collection of tests.
 
   Args:
     tests: List of tests to put in the collection.
   """
 
-  def __init__(self, tests=[]):
+  def __init__(self, tests=None):
+    if not tests:
+      tests = []
     self._lock = threading.Lock()
     self._tests = []
     self._tests_in_progress = 0
     # Used to signal that an item is avaliable or all items have been handled.
     self._item_avaliable_or_all_done = threading.Event()
     for t in tests:
       self.add(t)
 
   def _pop(self):
     """Pop a test from the collection.
@@ skipping 274 matching lines @@
   logging.info('Will run %d tests (%s): %s', len(tests), log_string, str(tests))
   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)