Make Fullscreen::requestFullscreen and exitFullscreen static

third_party/WebKit/Source/core/dom/DocumentFullscreen.cpp

 /*
  * Copyright (C) 2013, Google 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 23 matching lines @@
     return Fullscreen::fullscreenEnabled(document);
 }
 
 Element* DocumentFullscreen::fullscreenElement(Document& document)
 {
     return Fullscreen::fullscreenElementFrom(document);
 }
 
 void DocumentFullscreen::exitFullscreen(Document& document)
 {
-    Fullscreen::from(document).exitFullscreen();
+    Fullscreen::exitFullscreen(document);
 }
 
 Element* DocumentFullscreen::currentFullScreenElement(Document& document)
 {
     return Fullscreen::currentFullScreenElementFrom(document);
 }
 
 } // namespace blink