Revert of [Android] Remove android_commands and android_testrunner.

tools/android/appstats.py

 #!/usr/bin/python
 # 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.
 
 # 'top'-like memory/network polling for Android apps.
 
 import argparse
 import curses
 import os
 import re
 import sys
 import time
 
 from operator import sub
 
 sys.path.append(os.path.join(os.path.dirname(__file__),
                              os.pardir,
                              os.pardir,
                              'build',
                              'android'))
+from pylib import android_commands
 from pylib.device import device_errors
 from pylib.device import device_utils
 
 class Utils(object):
   """A helper class to hold various utility methods."""
 
   @staticmethod
   def FindLines(haystack, needle):
     """A helper method to find lines in |haystack| that contain the string
     |needle|."""
@@ skipping 66 matching lines @@
   @staticmethod
   def GetDeviceModel(adb):
     """Returns the model of the device with the |adb| connection."""
     return adb.GetProp('ro.product.model').strip()
 
   @staticmethod
   def GetDeviceToTrack(preset=None):
     """Returns a device serial to connect to.  If |preset| is specified it will
     return |preset| if it is connected and |None| otherwise.  If |preset| is not
     specified it will return the first connected device."""
-    devices = [d.adb.GetDeviceSerial()
-               for d in device_utils.DeviceUtils.HealthyDevices()]
+    devices = android_commands.GetAttachedDevices()
     if not devices:
       return None
 
     if preset:
       return preset if preset in devices else None
 
     return devices[0]
 
   @staticmethod
   def GetPidsToTrack(adb, default_pid=None, process_filter=None):
@@ skipping 882 matching lines @@
   if args.text_file:
     printer.PrettyFile(args.text_file,
                        snapshots,
                        args.diff_against_start,
                        args.show_mem,
                        args.show_net)
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv))