Revert of [Android] Remove android_commands and android_testrunner.

tools/android/appstats.py

Index: tools/android/appstats.py
diff --git a/tools/android/appstats.py b/tools/android/appstats.py
index ba53eacb6c593021b1ff9e0c635207ec11260899..a785417391cd3a57c9d03443a060459c6bc9a8f4 100755
--- a/tools/android/appstats.py
+++ b/tools/android/appstats.py
@@ -19,6 +19,7 @@
                              os.pardir,
                              'build',
                              'android'))
+from pylib import android_commands
 from pylib.device import device_errors
 from pylib.device import device_utils
 
@@ -105,8 +106,7 @@
     """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