Remove remaining unused imports in webkitpy.

third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/run_webkit_tests_unittest.py

Index: third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/run_webkit_tests_unittest.py
diff --git a/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/run_webkit_tests_unittest.py b/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/run_webkit_tests_unittest.py
index d1443f0dc7e71d9dc822767f46f0373ebc78ca9a..1bfd90e67482fcaf30ae3f0be2166e5dfc811741 100644
--- a/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/run_webkit_tests_unittest.py
+++ b/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/run_webkit_tests_unittest.py
@@ -28,28 +28,22 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-import StringIO
 import json
-import os
 import re
+import StringIO
 import sys
-import thread
 import unittest
 
-from webkitpy.common.system import outputcapture, path
-from webkitpy.common.system.crashlogs_unittest import make_mock_crash_report_darwin
-from webkitpy.common.system.systemhost import SystemHost
 from webkitpy.common.host import Host
 from webkitpy.common.host_mock import MockHost
+from webkitpy.common.system import outputcapture, path
+from webkitpy.common.system.systemhost import SystemHost
 
-from webkitpy.layout_tests import port
 from webkitpy.layout_tests import run_webkit_tests
 from webkitpy.layout_tests.models import test_expectations
 from webkitpy.layout_tests.models import test_failures
 from webkitpy.layout_tests.models import test_run_results
 from webkitpy.layout_tests.port import test
-from webkitpy.layout_tests.port.base import Port
-from webkitpy.tool import grammar
 
 
 def parse_args(extra_args=None, tests_included=False, new_results=False, print_nothing=True):