Add MediaKeys test with non-ASCII character

Also removes test specific timeouts now that the defaults have been
increased.

TEST=updated test passes

Review URL: https://codereview.chromium.org/226203005

git-svn-id: svn://svn.chromium.org/blink/trunk@170986 bbb929c8-8fbe-4397-9dbb-9b2b20218538