chromium/third_party/blink/web_tests/http/tests/xmlhttprequest/web-apps/README

There is a potential problem with some of these tests: Apache
sometimes returns 304s (correctly, I guess) instead of always running
the CGI script. I've tried to avoid this problem using 'no-store'
headers but I don't know if that's the right way to do this.

Note: 016 and 017 do not yet have pass criteria.