Provision Android devices after the 'device_status_check' step.

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.
+"""
+
+import os
+import sys
+import time
+
+from pylib import android_commands
+
+PULSE_PERIOD = 20

[navabi, 2013/03/27 19:53:32]

I thought the heartbeat was every 1 min, and the check on the device was every 2
minutes. Any reason to change the heartbeat to every 20 secs? It looks like the
daemon is still checking ever 2 mins.

[Siva Chandra, 2013/03/27 20:45:14]

I think the host should say 'I can see you' at a much faster rate than the
device checks. For example, if the host says at only twice the frequency the
device is checking, there could be a transient USB issue due which the host
pulse could miss reaching the device. This will make the device think that the
it lost connection with the host.

+
+def main():
+  while True:
+    devices = android_commands.GetAttachedDevices()
+    for device in devices:
+      android_cmd = android_commands.AndroidCommands(device)
+      android_cmd.EnableAdbRoot()
+      android_cmd.RunShellCommand('touch /sdcard/host_heartbeat')
+    time.sleep(PULSE_PERIOD)
+
+
+if __name__ == '__main__':
+  sys.exit(main())