Restore the HTMLVideoElement-specific prefixed fullscreen API behind a flag

Source/core/html/HTMLVideoElement.cpp

 /*
  * Copyright (C) 2007, 2008, 2009, 2010 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 103 matching lines @@
             if (renderer())
                 toRenderImage(renderer())->imageResource()->setImageResource(0);
         }
         // Notify the player when the poster image URL changes.
         if (player())
             player()->setPoster(posterImageURL());
     } else
         HTMLMediaElement::parseAttribute(name, value);
 }
 
+bool HTMLVideoElement::supportsFullscreen() const
+{
+    if (!document().page())
+        return false;
+
+    if (!player())
+        return false;
+
+    return true;
+}
+
 unsigned HTMLVideoElement::videoWidth() const
 {
     if (!player())
         return 0;
     return player()->naturalSize().width();
 }
 
 unsigned HTMLVideoElement::videoHeight() const
 {
     if (!player())
@@ skipping 56 matching lines @@
 }
 
 bool HTMLVideoElement::hasAvailableVideoFrame() const
 {
     if (!player())
         return false;
 
     return player()->hasVideo() && player()->readyState() >= MediaPlayer::HaveCurrentData;
 }
 
+void HTMLVideoElement::webkitEnterFullscreen(ExceptionState& exceptionState)
+{
+    if (isFullscreen())
+        return;
+
+    if (!supportsFullscreen()) {
+        exceptionState.throwDOMException(InvalidStateError, "This element does not support fullscreen mode.");
+        return;
+    }
+
+    enterFullscreen();
+}
+
+void HTMLVideoElement::webkitExitFullscreen()
+{
+    if (isFullscreen())
+        exitFullscreen();
+}
+
+bool HTMLVideoElement::webkitSupportsFullscreen()
+{
+    return supportsFullscreen();
+}
+
+bool HTMLVideoElement::webkitDisplayingFullscreen()
+{
+    return isFullscreen();
+}
+
 void HTMLVideoElement::didMoveToNewDocument(Document& oldDocument)
 {
     if (m_imageLoader)
         m_imageLoader->elementDidMoveToNewDocument();
     HTMLMediaElement::didMoveToNewDocument(oldDocument);
 }
 
 unsigned HTMLVideoElement::webkitDecodedFrameCount() const
 {
     if (!player())
@@ skipping 47 matching lines @@
 {
     return !hasSingleSecurityOrigin() || (!(player() && player()->didPassCORSAccessCheck()) && destinationSecurityOrigin->taintsCanvas(currentSrc()));
 }
 
 FloatSize HTMLVideoElement::sourceSize() const
 {
     return FloatSize(videoWidth(), videoHeight());
 }
 
 }