[Telemetry] Refactor common Android test harness functions.

This is a reland of crrev.com/62953024 which was reverted because
it broke other platforms.

Refactoring common cleanup code required by both
android_browser_finder.py and perf/setup.py and moving it into
pyblib/utils/test_environment.py.
Also, this change avoids killing twice the adb server when running
in a bot environment, where the adb restart is already invoked by
the bot steps.

BUG=268450
R=bulach@chromium.org,tonyg@chromium.org

Review URL: https://codereview.chromium.org/94683002

git-svn-id: http://src.chromium.org/svn/trunk/src/build@237815 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

android/pylib/android_commands.py

@@ -510,7 +510,9 @@ class AndroidCommands(object):
     while retry < 3:
       ret = cmd_helper.RunCmd(['pgrep', 'adb'])
       if ret == 0:
-        # pgrep fonud adb, start-server succeeded.
+        # pgrep found adb, start-server succeeded.
+        # Waiting for device to reconnect before returning success.
+        self._adb.SendCommand('wait-for-device')
         return 0
       retry += 1
       time.sleep(retry)

android/pylib/perf/setup.py

@@ -13,39 +13,13 @@ import signal
 import shutil
 import time
 
-from pylib import android_commands
-from pylib import cmd_helper
 from pylib import constants
 from pylib import forwarder
-from pylib import ports
+from pylib.utils import test_environment
 
 import test_runner
 
 
-def _KillPendingServers():
-  for retry in range(5):
-    for server in ['lighttpd', 'web-page-replay']:
-      pids = [p.pid for p in psutil.process_iter() if server in p.name]
-      for pid in pids:
-        try:
-          logging.warning('Killing %s %s', server, pid)
-          os.kill(pid, signal.SIGQUIT)
-        except Exception as e:
-          logging.warning('Failed killing %s %s %s', server, pid, e)
-  # Restart the adb server with taskset to set a single CPU affinity.
-  cmd_helper.RunCmd([constants.ADB_PATH, 'kill-server'])
-  cmd_helper.RunCmd(['taskset', '-c', '0', constants.ADB_PATH, 'start-server'])
-  cmd_helper.RunCmd(['taskset', '-c', '0', constants.ADB_PATH, 'root'])
-  i = 1
-  while not android_commands.GetAttachedDevices():
-    time.sleep(i)
-    i *= 2
-    if i > 10:
-      break
-
-  forwarder.Forwarder.UseMultiprocessing()
-
-
 def Setup(test_options):
   """Create and return the test runner factory and tests.
 
@@ -62,7 +36,8 @@ def Setup(test_options):
   os.makedirs(constants.PERF_OUTPUT_DIR)
 
   # Before running the tests, kill any leftover server.
-  _KillPendingServers()
+  test_environment.CleanupLeftoverProcesses()
+  forwarder.Forwarder.UseMultiprocessing()
 
   if test_options.single_step:
     # Running a single command, build the tests structure.

android/pylib/utils/test_environment.py

@@ -0,0 +1,35 @@
+# Copyright 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.
+
+import logging
+import os
+import psutil
+
+from pylib import android_commands
+
+def _KillWebServers():
+  for retry in xrange(5):
+    for server in ['lighttpd', 'web-page-replay']:
+      pids = [p.pid for p in psutil.process_iter() if server in p.name]
+      for pid in pids:
+        try:
+          logging.warning('Killing %s %s', server, pid)
+          os.kill(pid, signal.SIGQUIT)
+        except Exception as e:
+          logging.warning('Failed killing %s %s %s', server, pid, e)
+
+
+def CleanupLeftoverProcesses():
+  """Clean up the test environment, restarting fresh adb and HTTP daemons."""
+  _KillWebServers()
+  did_restart_host_adb = False
+  for device in android_commands.GetAttachedDevices():
+    adb = android_commands.AndroidCommands(device)
+    # Make sure we restart the host adb server only once.
+    if not did_restart_host_adb:
+      adb.RestartAdbServer()
+      did_restart_host_adb = True
+    adb.RestartAdbdOnDevice()
+    adb.EnableAdbRoot()
+    adb.WaitForDevicePm()