Revert of Remove the allowfullscreen exemption for the video-specific fullscreen API

Source/core/dom/Fullscreen.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
@@ skipping 42 matching lines @@
     virtual ~Fullscreen();
     static const char* supplementName();
     static Fullscreen& from(Document&);
     static Fullscreen* fromIfExists(Document&);
     static Element* fullscreenElementFrom(Document&);
     static Element* currentFullScreenElementFrom(Document&);
     static bool isFullScreen(Document&);
     static bool isActiveFullScreenElement(const Element&);
 
     enum RequestType {
-        // Element.requestFullscreen()
-        UnprefixedRequest,
-        // Element.webkitRequestFullscreen()/webkitRequestFullScreen() and
-        // HTMLVideoElement.webkitEnterFullscreen()/webkitEnterFullScreen()
-        PrefixedRequest,
-        // Fullscreen button in <video controls> and
-        // HTMLMediaElement::mediaPlayerRequestFullscreen()
-        InternalVideoRequest,
+        UnprefixedRequest, // Element.requestFullscreen()
+        PrefixedRequest, // Element.webkitRequestFullscreen() and webkitRequestFullScreen()
+        PrefixedVideoRequest, // HTMLVideoElement.webkitEnterFullscreen() and webkitEnterFullScreen()
     };
 
     void requestFullscreen(Element&, RequestType);
     static void fullyExitFullscreen(Document&);
     void exitFullscreen();
 
     static bool fullscreenEnabled(Document&);
     Element* fullscreenElement() const { return !m_fullScreenElementStack.isEmpty() ? m_fullScreenElementStack.last().first.get() : 0; }
 
     void didEnterFullScreenForElement(Element*);
@@ skipping 50 matching lines @@
 inline Fullscreen* Fullscreen::fromIfExists(Document& document)
 {
     if (!document.hasFullscreenSupplement())
         return 0;
     return fromIfExistsSlow(document);
 }
 
 } // namespace blink
 
 #endif // Fullscreen_h