Remove unused runtime setting requestanimationframeenabled
Remove unused runtime setting requestanimationframeenabled

This setting existed in WebKit but Chromium never changed it from its default value. We're removing all such unchanging settings in Blink, along with their associated code.

R=abarth@chromium.org
BUG=226711


Review URL: https://chromiumcodereview.appspot.com/14070003

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@148090 bbb929c8-8fbe-4397-9dbb-9b2b20218538

primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs