Revert of [Telemetry] Remove the logic of killing stray adb processes

telemetry/telemetry/internal/platform/android_device.py

Index: telemetry/telemetry/internal/platform/android_device.py
diff --git a/telemetry/telemetry/internal/platform/android_device.py b/telemetry/telemetry/internal/platform/android_device.py
index d99caedf82c151f9e930a325da9a1daa4a977939..79345a6cbd9139df29acd7c29238c1d576cbecf3 100644
--- a/telemetry/telemetry/internal/platform/android_device.py
+++ b/telemetry/telemetry/internal/platform/android_device.py
@@ -4,6 +4,7 @@
 
 import logging
 import os
+import subprocess
 
 from telemetry.core import util
 from telemetry.internal.platform import cros_device
@@ -14,6 +15,16 @@
 from devil.android import device_errors
 from devil.android import device_utils
 from devil.android.sdk import adb_wrapper
+
+
+def _KillStrayADBProcesses():
+  p = subprocess.Popen(['killall', 'adb'])
+  p.communicate()
+  if p.returncode:
+    logging.info('No adb process was killed')
+  else:
+    logging.info('Some adb process was killed')
+
 
 
 class AndroidDevice(device.Device):
@@ -59,7 +70,12 @@
   the returned list. The arguments specify what devices to include in the list.
   """
 
-  device_serials = _ListSerialsOfHealthyOnlineDevices(blacklist)
+  try:
+    device_serials = _ListSerialsOfHealthyOnlineDevices(blacklist)
+  # Sometimes stray adb processes can interfere with using adb.
+  except device_errors.AdbCommandFailedError:
+    _KillStrayADBProcesses()
+    device_serials = _ListSerialsOfHealthyOnlineDevices(blacklist)
 
   # The monsoon provides power for the device, so for devices with no
   # real battery, we need to turn them on after the monsoon enables voltage