Android perf tests: kill adbd on the device after running a test.

There's some data indicating that adbd on the device sometimes
spontaneously restores its connection.
After running a test, let's kill adbd and wait for bit.

This is a speculative change to try to make the bots healthier.

BUG=

Review URL: https://codereview.chromium.org/25574002

git-svn-id: http://src.chromium.org/svn/trunk/src/build@226762 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

android/pylib/android_commands.py

@@ -459,6 +459,14 @@ class AndroidCommands(object):
     if out.strip() != 'remount succeeded':
       raise errors.MsgException('Remount failed: %s' % out)
 
+  def KillAdbdDevice(self):
+    logging.info('Killing adbd on the device...')
+    adb_pids = self.ExtractPid('adbd')
+    if adb_pids:
+      self.RunShellCommandWithSU('kill %s' % ' '.join(adb_pids))
+    logging.info('Waiting for device to settle...')
+    time.sleep(5)
+
   def RestartAdbServer(self):
     """Restart the adb server."""
     ret = self.KillAdbServer()

android/pylib/perf/test_runner.py

@@ -50,6 +50,7 @@ import pickle
 import os
 import sys
 
+from pylib import android_commands
 from pylib import constants
 from pylib.base import base_test_result
 from pylib.base import base_test_runner
@@ -153,6 +154,11 @@ class TestRunner(base_test_runner.BaseTestRunner):
     }
     self._SaveResult(persisted_result)
 
+    try:
+      self.adb.KillAdbdDevice()
+    except Exception as e:
+      logging.error('Exception when killing adbd %s', e)
+
     return (output, result_type)
 
   def RunTest(self, test_name):