Add device_serial

devil/devil/android/logcat_monitor.py

 # Copyright 2015 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.
 
 # pylint: disable=unused-argument
 
 import errno
 import logging
 import os
 import re
@@ skipping 34 matching lines @@
     self._output_file = output_file
     self._record_file = None
     self._record_file_lock = threading.Lock()
     self._record_thread = None
     self._stop_recording_event = threading.Event()
 
   @property
   def output_file(self):
     return self._output_file
 
+  @property
+  def get_device_serial(self):
+    return self._adb.GetDeviceSerial()
+
   @decorators.WithTimeoutAndRetriesDefaults(10, 0)
   def WaitFor(self, success_regex, failure_regex=None, timeout=None,
               retries=None):
     """Wait for a matching logcat line or until a timeout occurs.
 
     This will attempt to match lines in the logcat against both |success_regex|
     and |failure_regex| (if provided). Note that this calls re.search on each
     logcat line, not re.match, so the provided regular expressions don't have
     to match an entire line.
 
@@ skipping 168 matching lines @@
     with self._record_file_lock:
       if self._record_file:
         logging.warning(
             'Need to call |Close| on the logcat monitor when done!')
         self._record_file.close()
 
 
 class LogcatMonitorCommandError(device_errors.CommandFailedError):
   """Exception for errors with logcat monitor commands."""
   pass