The goal of this manual test is to ensure that :visited links are partitioned by link URL, top-level site, and frame origin.
(1) Clear any browsing data, including history.
(2) Click on the link in the first iframe. The link in this top-level frame should turn purple. The link in the second iframe should remain blue.
(3) Finally, click on the browser's back arrow.
Test PASSES if: the top-level link (I should turn purple!) is purple, the first iframe link (Click me! (Then I should turn purple)) is purple, and the second iframe link (I should stay blue) is blue. All other conditions: the test FAILS.