Remove the fullscreen element stack exemption for webkitRequestFullScreen()

Source/core/dom/FullscreenElementStack.cpp

 /*
  * 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 168 matching lines @@
         return false;
 
     // element's node document's fullscreen enabled flag is set.
     if (!fullscreenIsAllowedForAllOwners(element.document())) {
         if (requestType == PrefixedVideoRequest)
             UseCounter::count(element.document(), UseCounter::VideoFullscreenAllowedExemption);
         else
             return false;
     }
 
-    // element's node document fullscreen element stack is either empty or its top element is an
+    // element's node document's fullscreen element stack is either empty or its top element is an
     // ancestor of element.
-    if (Element* lastElementOnStack = fullscreenElementFrom(element.document())) {
-        if (!element.isDescendantOf(lastElementOnStack)) {
-            if (requestType == PrefixedMozillaRequest || requestType == PrefixedMozillaAllowKeyboardInputRequest)
-                UseCounter::count(element.document(), UseCounter::LegacyFullScreenErrorExemption);
-            else
-                return false;
-        }
+    if (Element* topElement = fullscreenElementFrom(element.document())) {
+        if (!element.isDescendantOf(topElement))
+            return false;
     }
 
     // element has no ancestor element whose local name is iframe and namespace is the HTML
     // namespace.
     if (Traversal<HTMLIFrameElement>::firstAncestor(element))
         return false;
 
     return true;
 }
 
@@ skipping 398 matching lines @@
 void FullscreenElementStack::trace(Visitor* visitor)
 {
     visitor->trace(m_fullScreenElement);
     visitor->trace(m_fullScreenElementStack);
     visitor->trace(m_fullScreenRenderer);
     visitor->trace(m_eventQueue);
     DocumentSupplement::trace(visitor);
 }
 
 } // namespace blink