[Android] Change object types from AndroidCommands to DeviceUtils in build/android/.

build/android/host_heartbeat.py

 #!/usr/bin/env python
 #
 # Copyright (c) 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.
 
 """Sends a heart beat pulse to the currently online Android devices.
 This heart beat lets the devices know that they are connected to a host.
 """
 # pylint: disable=W0702
 
 import sys
 import time
 
 from pylib import android_commands
+from pylib.device import device_utils
 
 PULSE_PERIOD = 20
 
 def main():
   while True:
     try:
       devices = android_commands.GetAttachedDevices()
-      for device in devices:
-        android_cmd = android_commands.AndroidCommands(device)
-        android_cmd.RunShellCommand('touch /sdcard/host_heartbeat')
+      for device_serial in devices:
+        device_utils.DeviceUtils(device_serial).RunShellCommand(
+            'touch /sdcard/host_heartbeat')
     except:
       # Keep the heatbeat running bypassing all errors.
       pass
     time.sleep(PULSE_PERIOD)
 
 
 if __name__ == '__main__':
   sys.exit(main())