[Android] Don't use a device blacklist if one isn't provided.

build/android/pylib/local/device/local_device_environment.py

 # Copyright 2014 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.
 
 from devil.android import device_blacklist
 from devil.android import device_errors
 from devil.android import device_utils
 from devil.android.sdk import adb_wrapper
 from devil.utils import parallelizer
 from pylib.base import environment
 
 
 class LocalDeviceEnvironment(environment.Environment):
 
   def __init__(self, args, _error_func):
     super(LocalDeviceEnvironment, self).__init__()
-    self._blacklist = device_blacklist.Blacklist(
-        args.blacklist_file or device_blacklist.BLACKLIST_JSON)
+    self._blacklist = (device_blacklist.Blacklist(args.blacklist_file)
+                       if args.blacklist_file
+                       else None)
     self._device_serial = args.test_device
     self._devices = []
     self._max_tries = 1 + args.num_retries
     self._tool_name = args.tool
 
   #override
   def SetUp(self):
     available_devices = device_utils.DeviceUtils.HealthyDevices(
         self._blacklist)
     if not available_devices:
@@ skipping 20 matching lines @@
     return self._max_tries
 
   @property
   def tool(self):
     return self._tool_name
 
   #override
   def TearDown(self):
     pass