third_party/blink/web_tests/external/wpt/user-timing/clear_all_marks.any.js

test(function() {
    self.performance.mark("mark1");
    self.performance.mark("mark2");

    // test that two marks have been created
    var entries = self.performance.getEntriesByType("mark");
    assert_equals(entries.length, 2, "Two marks have been created for this test.");

    // clear all marks
    self.performance.clearMarks();

    // test that all marks were cleared
    entries = self.performance.getEntriesByType("mark");

    assert_equals(entries.length, 0, "All marks have been cleared.");

}, "Clearing all marks remove all of them.");