Make port unmapping errors non fatal.

build/android/pylib/forwarder.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 re
 import sys
 import threading
 import time
@@ skipping 110 matching lines @@
 
   def _UnmapDevicePortInternalLocked(self, device_port):
     if not device_port in self._device_to_host_port_map:
       return
     redirection_command = [
         '--serial-id=' + self._adb.Adb().GetSerialNumber(), '--unmap',
         str(device_port)]
     (exit_code, output) = cmd_helper.GetCmdStatusAndOutput(
         [self._host_forwarder_path] + redirection_command)
     if exit_code != 0:
-      raise Exception('%s exited with %d:\n%s' % (
+      logging.error('%s exited with %d:\n%s' % (
           self._host_forwarder_path, exit_code, '\n'.join(output)))
     host_port = self._device_to_host_port_map[device_port]
     del self._device_to_host_port_map[device_port]
     del self._host_to_device_port_map[host_port]
 
   @staticmethod
   def KillHost(build_type='Debug'):
     """Kills the forwarder process running on the host.
 
     Args:
@@ skipping 42 matching lines @@
   def DevicePortForHostPort(self, host_port):
     """Returns the device port that corresponds to a given host port."""
     with self._lock:
       return self._host_to_device_port_map.get(host_port)
 
   def Close(self):
     """Releases the previously forwarded ports."""
     with self._lock:
       for device_port in self._device_to_host_port_map.copy():
         self._UnmapDevicePortInternalLocked(device_port)