Bug 1300805 - Remove media.webvtt.enabled pref. r=kinetik,smaug

This API has been deployed to release for some time. There isi
no longer value to being able to quickly disable it.

MozReview-Commit-ID: Jj6CyWzP93g

dom/html/HTMLTrackElement.cpp

@@ -50,10 +50,6 @@ nsGenericHTMLElement*
 NS_NewHTMLTrackElement(already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo,
                        mozilla::dom::FromParser aFromParser)
 {
-  if (!mozilla::dom::HTMLTrackElement::IsWebVTTEnabled()) {
-    return new mozilla::dom::HTMLUnknownElement(aNodeInfo);
-  }
-
   return new mozilla::dom::HTMLTrackElement(aNodeInfo);
 }
 
@@ -177,13 +173,6 @@ HTMLTrackElement::WrapNode(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
   return HTMLTrackElementBinding::Wrap(aCx, this, aGivenProto);
 }
 
-bool
-HTMLTrackElement::IsWebVTTEnabled()
-{
-  // Our callee does not use its arguments.
-  return HTMLTrackElementBinding::ConstructorEnabled(nullptr, nullptr);
-}
-
 TextTrack*
 HTMLTrackElement::GetTrack()
 {