Remove the webkitallowfullscreen content attribute

Source/core/frame/UseCounter.h

 /*
  * Copyright (C) 2012 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 291 matching lines @@
         PrefixedCancelRequestAnimationFrame = 305,
         NamedNodeMapGetNamedItem = 306,
         NamedNodeMapSetNamedItem = 307,
         NamedNodeMapRemoveNamedItem = 308,
         NamedNodeMapItem = 309,
         NamedNodeMapGetNamedItemNS = 310,
         NamedNodeMapSetNamedItemNS = 311,
         NamedNodeMapRemoveNamedItemNS = 312,
         OpenWebDatabaseInWorker = 313, // This didn't work because of crbug.com/376039. Available since M37.
         OpenWebDatabaseSyncInWorker = 314, // This didn't work because of crbug.com/376039. Available since M37.
-        PrefixedAllowFullscreenAttribute = 315,
         XHRProgressEventPosition = 316,
         XHRProgressEventTotalSize = 317,
         PrefixedDocumentIsFullscreen = 318,
         PrefixedDocumentFullScreenKeyboardInputAllowed = 319,
         PrefixedDocumentCurrentFullScreenElement = 320,
         PrefixedDocumentCancelFullScreen = 321,
         PrefixedDocumentFullscreenEnabled = 322,
         PrefixedDocumentFullscreenElement = 323,
         PrefixedDocumentExitFullscreen = 324,
         // The above items are available in M35 branch.
@@ skipping 217 matching lines @@
 
     void updateMeasurements();
 
     OwnPtr<BitVector> m_countBits;
     BitVector m_CSSFeatureBits;
 };
 
 } // namespace WebCore
 
 #endif // UseCounter_h