Remove use of wdiff from layout test runner.

third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/test.py

 # Copyright (C) 2010 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 454 matching lines @@
         return set(['failures/expected/skip_text.html',
                     'failures/unexpected/skip_pass.html',
                     'virtual/skipped/failures/expected'])
 
     def name(self):
         return self._name
 
     def operating_system(self):
         return self._operating_system
 
-    def _path_to_wdiff(self):
-        return None
-
     def default_results_directory(self):
         return '/tmp/layout-test-results'
 
     def setup_test_run(self):
         pass
 
     def _driver_class(self):
         return TestDriver
 
     def start_http_server(self, additional_dirs, number_of_drivers):
@@ skipping 139 matching lines @@
         else:
             image = test.actual_image
         return DriverOutput(actual_text, image, test.actual_checksum, audio,
                             crash=(crash or web_process_crash), crashed_process_name=crashed_process_name,
                             crashed_pid=crashed_pid, crash_log=crash_log,
                             test_time=time.time() - start_time, timeout=test.timeout, error=test.error, pid=self.pid,
                             leak=test.leak)
 
     def stop(self):
         self.started = False