Update from https://crrev.com/317530

testing/legion/host_controller.py

-# Copyright 2015 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.
-
-"""Defines the host controller base library.
-
-This module is the basis on which host controllers are built and executed.
-"""
-
-import logging
-import sys
-
-#pylint: disable=relative-import
-import client_lib
-import common_lib
-import discovery_server
-
-
-class HostController(object):
-  """The base host controller class."""
-
-  def __init__(self):
-    self._discovery_server = discovery_server.DiscoveryServer()
-
-  def SetUp(self):
-    """Setup method used by the subclass."""
-    pass
-
-  def Task(self):
-    """Main task method used by the subclass."""
-    pass
-
-  def TearDown(self):
-    """Teardown method used by the subclass."""
-    pass
-
-  def NewClient(self, *args, **kwargs):
-    controller = client_lib.ClientController(*args, **kwargs)
-    self._discovery_server.RegisterClientCallback(
-        controller.otp, controller.OnConnect)
-    return controller
-
-  def RunController(self):
-    """Main entry point for the controller."""
-    print ' '.join(sys.argv)
-    common_lib.InitLogging()
-    self._discovery_server.Start()
-
-    error = None
-    tb = None
-    try:
-      self.SetUp()
-      self.Task()
-    except Exception as e:
-      # Defer raising exceptions until after TearDown and _TearDown are called.
-      error = e
-      tb = sys.exc_info()[-1]
-    try:
-      self.TearDown()
-    except Exception as e:
-      # Defer raising exceptions until after _TearDown is called.
-      # Note that an error raised here will obscure any errors raised
-      # previously.
-      error = e
-      tb = sys.exc_info()[-1]
-
-    self._discovery_server.Shutdown()
-    client_lib.ClientController.ReleaseAllControllers()
-    if error:
-      raise error, None, tb  #pylint: disable=raising-bad-type