This directory is for adding short performance tests that will be tracked in
Talos and receive regression alerts.

To add a test:

1)  Create a test HTML file which includes <script src="util.js"></script>
2)  In that file, have an onload handler which does the following:
   i) Any pre-test setup needed.
  ii) A call to perf_start().
 iii) The test steps.
  iv) A call to perf_finish().
3)  Add your test to the perf_reftest_singletons.manifest file.
4)  Add your test to the list in build/pgo/index.html, if it should be used
    for profile-guided optimization.
