at two measures have been created
            entries = window.performance.getEntriesByType("measure");
            test_equals(entries.length, 2, "Two measures have been created for this test.");

            // clear non-existent measure
            window.performance.clearMeasures(measureName3);

            // test that "measure1" still exists
            entries = window.performance.getEntriesByName(measureName1);
            test_true(entries[0].name == measureName1,
                      "After a cal