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

tools/perf/measurements/loading_trace_unittest.py

Index: tools/perf/measurements/loading_trace_unittest.py
diff --git a/tools/perf/measurements/loading_trace_unittest.py b/tools/perf/measurements/loading_trace_unittest.py
index b83d2becebb482c32d9da9382f4eb6f2ebb1e9b6..cc7b912dd825714595b9525aa65d9c5a2e1bda5d 100644
--- a/tools/perf/measurements/loading_trace_unittest.py
+++ b/tools/perf/measurements/loading_trace_unittest.py
@@ -1,13 +1,13 @@
 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
+
 from measurements import loading_trace
 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
 
-class LoadingTraceUnitTest(
-      page_measurement_unittest_base.PageMeasurementUnitTestBase):
+class LoadingTraceUnitTest(page_test_test_case.PageTestTestCase):
   def setUp(self):
     self._options = options_for_unittests.GetCopy()
     self._options.browser_options.wpr_mode = wpr_modes.WPR_OFF