Move t.p.PageMeasurementUnitTestBase to t.testing.PageTestTestCase.

tools/perf/measurements/thread_times_unittest.py

Index: tools/perf/measurements/thread_times_unittest.py
diff --git a/tools/perf/measurements/thread_times_unittest.py b/tools/perf/measurements/thread_times_unittest.py
index b0103ea34a531fc877ee0fa779aeb4046a97658f..e07c61e0578e433d36a9a1bead5765f8498bd97c 100644
--- a/tools/perf/measurements/thread_times_unittest.py
+++ b/tools/perf/measurements/thread_times_unittest.py
@@ -6,15 +6,13 @@ from measurements import thread_times
 from measurements import smoothness_unittest
 from metrics import timeline
 from telemetry.core import wpr_modes
-from telemetry.page import page_measurement_unittest_base
-
+from telemetry.testing import page_test_test_case
 from telemetry.unittest import options_for_unittests
 from telemetry.unittest import test
 
 
 
-class ThreadTimesUnitTest(
-      page_measurement_unittest_base.PageMeasurementUnitTestBase):
+class ThreadTimesUnitTest(page_test_test_case.PageTestTestCase):
   def setUp(self):
     self._options = options_for_unittests.GetCopy()
     self._options.browser_options.wpr_mode = wpr_modes.WPR_OFF