chromium_android: fix dangerous default value

scripts/slave/recipe_modules/chromium_android/api.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.
 
 import contextlib
 import datetime
 import json
 import os
 import pipes
 import re
@@ skipping 350 matching lines @@
               'file format is compatible')
 
   def device_status_check(self, restart_usb=False, **kwargs):
     # TODO(bpastene): Remove once chromium revisions prior to
     # crrev.com/1faecde0c03013b6cd725da413339c60223f8948 are no longer tested.
     # See crbug.com/619707 for context.
     self.revert_device_file_format()
     self.device_recovery()
     return self.device_status()
 
-  def host_info(self, args=[], **kwargs):
+  def host_info(self, args=None, **kwargs):
+    args = args or []
     results = None
     try:
       with self.handle_exit_codes():
         if self.known_devices_file:
           known_devices_arg = ['--known-devices-file', self.known_devices_file]
           args.extend(['--args', self.m.json.input(known_devices_arg)])
         args.extend(['run', '--output', self.m.json.output()])
         results = self.m.step(
             'Host Info',
             [self.m.path['checkout'].join('testing', 'scripts',
@@ skipping 1110 matching lines @@
       script = self.c.test_runner
       if wrapper_script_suite_name:
         script = self.m.chromium.output_dir.join('bin', 'run_%s' %
                                                  wrapper_script_suite_name)
       else:
         env = kwargs.get('env', {})
         env['CHROMIUM_OUTPUT_DIR'] = env.get('CHROMIUM_OUTPUT_DIR',
                                              self.m.chromium.output_dir)
         kwargs['env'] = env
       return self.m.python(step_name, script, args, **kwargs)