[Android] Fix RunInSubThread extra for ASAN.

build/android/pylib/gtest/test_package_apk.py

 # Copyright (c) 2012 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.
 
 """Defines TestPackageApk to help run APK-based native tests."""
 # pylint: disable=W0212
 
 import itertools
 import logging
 import os
@@ skipping 26 matching lines @@
         constants.GetOutDirectory(), '%s_apk' % suite_name,
         '%s-debug.apk' % suite_name)
     if suite_name == 'content_browsertests':
       self._package_info = constants.PACKAGE_INFO['content_browsertests']
     elif suite_name == 'components_browsertests':
       self._package_info = constants.PACKAGE_INFO['components_browsertests']
     else:
       self._package_info = constants.PACKAGE_INFO['gtest']
 
     if suite_name == 'net_unittests':
-      self._extras = {'RunInSubThread': ''}
+      self._extras = {'RunInSubThread': None}
     else:
       self._extras = []
 
   def _CreateCommandLineFileOnDevice(self, device, options):
     device.WriteFile(self._package_info.cmdline_file,
                      self.suite_name + ' ' + options)
 
   def _GetFifo(self):
     # The test.fifo path is determined by:
     # testing/android/native_test/java/src/org/chromium/native_test/
@@ skipping 90 matching lines @@
 
   #override
   def Install(self, device):
     self.tool.CopyFiles(device)
     device.Install(self.suite_path)
 
   #override
   def PullAppFiles(self, device, files, directory):
     local_device_gtest_run.PullAppFilesImpl(
         device, self._package_info.package, files, directory)