[devil] Make LogcatMonitor expose its AdbWrapper instance via property.

devil/devil/android/logcat_monitor.py

Index: devil/devil/android/logcat_monitor.py
diff --git a/devil/devil/android/logcat_monitor.py b/devil/devil/android/logcat_monitor.py
index 9ec94125b94c42225bfd6b58f888f95619173b40..bf30d409bf1e027e4b26e24acbf26e9ffc92c801 100644
--- a/devil/devil/android/logcat_monitor.py
+++ b/devil/devil/android/logcat_monitor.py
@@ -236,6 +236,10 @@ class LogcatMonitor(object):
             'Need to call |Close| on the logcat monitor when done!')
         self._record_file.close()
 
+  @property
+  def adb(self):
+    return self._adb
+
 
 class LogcatMonitorCommandError(device_errors.CommandFailedError):
   """Exception for errors with logcat monitor commands."""