Sync requestFullscreen() and exitFullscreen() algorithms with the spec

third_party/WebKit/Source/core/layout/compositing/PaintLayerCompositor.cpp

 /*
  * Copyright (C) 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 152 matching lines @@
   // Recursively find the document that is in fullscreen.
   Element* fullscreenElement = Fullscreen::fullscreenElementFrom(document);
   Document* contentDocument = &document;
   while (fullscreenElement && fullscreenElement->isFrameOwnerElement()) {
     contentDocument =
         toHTMLFrameOwnerElement(fullscreenElement)->contentDocument();
     if (!contentDocument)
       return nullptr;
     fullscreenElement = Fullscreen::fullscreenElementFrom(*contentDocument);
   }
-  // Get the current fullscreen element from the document.
-  // TODO(foolip): When |currentFullScreenElementFrom| is removed, this will
-  // become a no-op and can be removed. https://crbug.com/402421
-  fullscreenElement =
-      Fullscreen::currentFullScreenElementFrom(*contentDocument);
   if (!isHTMLVideoElement(fullscreenElement))
     return nullptr;
   LayoutObject* layoutObject = fullscreenElement->layoutObject();
   if (!layoutObject)
     return nullptr;
   return toLayoutVideo(layoutObject);
 }
 
 void PaintLayerCompositor::updateIfNeededRecursive() {
   SCOPED_BLINK_UMA_HISTOGRAM_TIMER("Blink.Compositing.UpdateTime");
@@ skipping 1147 matching lines @@
   } else if (graphicsLayer == m_scrollLayer.get()) {
     name = "Frame Scrolling Layer";
   } else {
     ASSERT_NOT_REACHED();
   }
 
   return name;
 }
 
 }  // namespace blink