Remove unused imports in webkitpy.

third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/controllers/manager.py

 # Copyright (C) 2010 Google Inc. All rights reserved.
 # Copyright (C) 2010 Gabor Rapcsanyi (rgabor@inf.u-szeged.hu), University of Szeged
 #
 # 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
@@ skipping 19 matching lines @@
 """The Manager orchestrates the overall process of running layout tests.
 
 This includes finding tests to run, reading the test expectations,
 starting the required helper servers, deciding the order and way to
 run the tests, retrying fails tests and collecting the test results,
 including crash logs, and mismatches with expectations.
 
 The Manager object has a constructor and one main method called run.
 """
 
-import datetime
 import json
 import logging
 import random
 import sys
 import time
 
 from webkitpy.common.net.file_uploader import FileUploader
 from webkitpy.layout_tests.controllers.layout_test_finder import LayoutTestFinder
 from webkitpy.layout_tests.controllers.layout_test_runner import LayoutTestRunner
 from webkitpy.layout_tests.controllers.test_result_writer import TestResultWriter
@@ skipping 499 matching lines @@
 
         stats = {}
         for result in initial_results.results_by_name.values():
             if result.type != test_expectations.SKIP:
                 stats[result.test_name] = {'results': (_worker_number(result.worker_name), result.test_number, result.pid, int(
                     result.test_run_time * 1000), int(result.total_run_time * 1000))}
         stats_trie = {}
         for name, value in stats.iteritems():
             json_results_generator.add_path_to_trie(name, value, stats_trie)
         return stats_trie