Handle content_shell failing to start on android as device going offline.

Tools/Scripts/webkitpy/layout_tests/port/driver.py

 # Copyright (C) 2011 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
@@ skipping 64 matching lines @@
         self.measurements = measurements
         self.timeout = timeout
         self.error = error  # stderr output
         self.pid = pid
         self.device_offline = device_offline
 
     def has_stderr(self):
         return bool(self.error)
 
 
+class DeviceOffline(Exception):
+    pass
+
+
 class Driver(object):
     """object for running test(s) using content_shell or other driver."""
 
     def __init__(self, port, worker_number, pixel_tests, no_timeout=False):
         """Initialize a Driver to subsequently run tests.
 
         Typically this routine will spawn content_shell in a config
         ready for subsequent input.
 
         port - reference back to the port object.
@@ skipping 385 matching lines @@
         self.content = str()  # FIXME: Should be bytearray() once we require Python 2.6.
         self.decoded_content = None
         self.malloc = None
         self.js_heap = None
 
     def decode_content(self):
         if self.encoding == 'base64' and self.content is not None:
             self.decoded_content = base64.b64decode(self.content)
         else:
             self.decoded_content = self.content