Remove unused imports in webkitpy.

third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline.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 24 matching lines @@
 import threading
 import time
 import traceback
 import urllib
 import urllib2
 
 from webkitpy.common.checkout.baselineoptimizer import BaselineOptimizer
 from webkitpy.common.memoized import memoized
 from webkitpy.common.system.executive import ScriptError
 from webkitpy.layout_tests.controllers.test_result_writer import TestResultWriter
-from webkitpy.layout_tests.models import test_failures
 from webkitpy.layout_tests.models.test_expectations import TestExpectations, BASELINE_SUFFIX_LIST, SKIP
 from webkitpy.layout_tests.port import builders
 from webkitpy.layout_tests.port import factory
 from webkitpy.tool.multicommandtool import AbstractDeclarativeCommand
 
 
 _log = logging.getLogger(__name__)
 
 
 # FIXME: Should TestResultWriter know how to compute this string?
@@ skipping 951 matching lines @@
                 self._tool.scm().checkout_branch(old_branch_name_or_ref)
         else:
             self._log_queue.put(self.QUIT_LOG)
         log_thread.join()
 
     def execute(self, options, args, tool):
         self._verbose = options.verbose
         while True:
             self._do_one_rebaseline()
             time.sleep(self.SLEEP_TIME_IN_SECONDS)