Safari is using WebKit. WebKit started as a fork of the KHTML and KJS libraries from KDE and has since been further developed by KDE contributors, Apple, Google, Nokia, Bitstream, BlackBerry, Sony, Igalia and others. On April 3, 2013, Google announced that it had forked WebCore, a component of WebKit, to be used in future versions of Google Chrome, under the name Blink. Source: Wikipedia
Unfortunately EtherNet over HDMI exists so your your TV can still access the Internet if the Apple TV or Nvidia Shield has Internet access. To prevent that you have to make sure use older HDMI cable less then HDMI 1.4.