WebKit: UXSS via CachedFrameBase::restore

This is similar to the case https://bugs.chromium.org/p/project-zero/issues/detail?id=1151. But this time, javascript handlers may be fired in FrameLoader::open. void FrameLoader::openCachedFrameBase& cachedFrame ... cleardocument, true, true, cachedFrame.isMainFrame; Click anywhere... function...