Go to trailers.apple.com, play a trailer, take it fullscreen. The HUD is missing.
<rdar://problem/26519589>
Created attachment 280147 [details] Patch
Comment on attachment 280147 [details] Patch No way to make a test case?
Created attachment 280162 [details] Patch for landing (with test)
Created attachment 280183 [details] Patch for landing (with test)
Committed r201530: <http://trac.webkit.org/changeset/201530>