[webdriver] Add visibility test for hidden parent with visible children (#247)

In an overflow context where overflow is hidden, absolutely positioned
child elements are still visible in the browser.  The parent container
is by webdriver also considered visible for the reason of
interactability.

View on GitHub: https://github.com/w3c/web-platform-tests/pull/247

Received on Friday, 12 July 2013 12:17:31 UTC