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

Source/core/html/HTMLMediaElement.cpp

 /*
  * Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 2764 matching lines @@
 }
 
 void HTMLMediaElement::mediaPlayerRequestFullscreen()
 {
     WTF_LOG(Media, "HTMLMediaElement::mediaPlayerRequestFullscreen(%p)", this);
 
     // The player is responsible for only invoking this callback in response to
     // user interaction or when it is technically required to play the video.
     UserGestureIndicator gestureIndicator(DefinitelyProcessingNewUserGesture);
 
-    Fullscreen::from(document()).requestFullscreen(*this, Fullscreen::InternalVideoRequest);
+    enterFullscreen();
 }
 
 void HTMLMediaElement::mediaPlayerRequestSeek(double time)
 {
     // The player is the source of this seek request.
     if (m_mediaController) {
         m_mediaController->setCurrentTime(time);
         return;
     }
     setCurrentTime(time, ASSERT_NO_EXCEPTION);
@@ skipping 337 matching lines @@
         m_mediaController->clearExecutionContext();
 #endif
     ActiveDOMObject::contextDestroyed();
 }
 
 bool HTMLMediaElement::isFullscreen() const
 {
     return Fullscreen::isActiveFullScreenElement(*this);
 }
 
+void HTMLMediaElement::enterFullscreen()
+{
+    WTF_LOG(Media, "HTMLMediaElement::enterFullscreen(%p)", this);
+
+    Fullscreen::from(document()).requestFullscreen(*this, Fullscreen::PrefixedVideoRequest);
+}
+
+void HTMLMediaElement::exitFullscreen()
+{
+    WTF_LOG(Media, "HTMLMediaElement::exitFullscreen(%p)", this);
+
+    Fullscreen::from(document()).exitFullscreen();
+}
+
 void HTMLMediaElement::didBecomeFullscreenElement()
 {
     if (mediaControls())
         mediaControls()->enteredFullscreen();
     if (RuntimeEnabledFeatures::overlayFullscreenVideoEnabled() && isHTMLVideoElement())
         document().layoutView()->compositor()->setNeedsCompositingUpdate(CompositingUpdateRebuildTree);
 }
 
 void HTMLMediaElement::willStopBeingFullscreenElement()
 {
@@ skipping 507 matching lines @@
 
 #if ENABLE(WEB_AUDIO)
 void HTMLMediaElement::clearWeakMembers(Visitor* visitor)
 {
     if (!Heap::isHeapObjectAlive(m_audioSourceNode) && audioSourceProvider())
         audioSourceProvider()->setClient(nullptr);
 }
 #endif
 
 }