Remove unused imports in webkitpy with using autoflake.

third_party/WebKit/Tools/Scripts/webkitpy/w3c/test_importer.py

 # Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions
 # are met:
 #
 # 1. Redistributions of source code must retain the above
 #    copyright notice, this list of conditions and the following
 #    disclaimer.
 # 2. Redistributions in binary form must reproduce the above
@@ skipping 54 matching lines @@
        a timestamp, the W3C Mercurial changeset if available, the list of CSS
        properties used that require prefixes, the list of imported files, and
        guidance for future test modification and maintenance. On subsequent
        imports, this file is read to determine if files have been
        removed in the newer changesets.  The script removes these files
        accordingly.
 """
 
 # FIXME: Change this file to use the Host abstractions rather that os, sys, shutils, etc.
 
-import datetime
 import logging
 import mimetypes
 import optparse
 import os
 import shutil
 import sys
 
 from webkitpy.common.host import Host
 from webkitpy.common.webkit_finder import WebKitFinder
 from webkitpy.common.system.executive import ScriptError
@@ skipping 322 matching lines @@
         """ Creates a destination directory that mirrors that of the source directory """
 
         new_subpath = self.dir_to_import[len(self.top_of_repo):]
 
         destination_directory = os.path.join(self.destination_directory, new_subpath)
 
         if not os.path.exists(destination_directory):
             os.makedirs(destination_directory)
 
         _log.info('Tests will be imported into: %s', destination_directory)