Move Python setup/tear down logic into Forwarder itself.

tools/telemetry/telemetry/core/chrome/android_browser_backend.py

 # Copyright (c) 2012 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 subprocess
 import sys
 import time
 
@@ skipping 146 matching lines @@
     self._adb = backend_settings.adb
     self._backend_settings = backend_settings
     self._saved_cmdline = None
     if not options.keep_test_server_ports:
       adb_commands.ResetTestServerPortAllocation()
     self._port = adb_commands.AllocateTestServerPort()
 
     # Kill old browser.
     self._adb.CloseApplication(self._backend_settings.package)
 
-    adb_commands.Forwarder.KillDevice(self._adb)
-    if not options.keep_test_server_ports:
-      adb_commands.Forwarder.KillHost()
-
     if self._adb.Adb().CanAccessProtectedFileContents():
       if not options.dont_override_profile:
         self._backend_settings.RemoveProfile()
       if options.profile_dir:
         self._backend_settings.PushProfile(options.profile_dir)
 
     # Set up the command line.
     self._saved_cmdline = ''.join(self._adb.Adb().GetProtectedFileContents(
         self._backend_settings.cmdline_file) or [])
     args = [backend_settings.pseudo_exec_name]
@@ skipping 101 matching lines @@
                               'tombstones.py')
     if os.path.exists(tombstones):
       ret += Decorate('Tombstones',
                       subprocess.Popen([tombstones, '-w', '--device',
                                         self._adb.device()],
                                        stdout=subprocess.PIPE).communicate()[0])
     return ret
 
   def CreateForwarder(self, *port_pairs):
     return adb_commands.Forwarder(self._adb, *port_pairs)