Remove unused feature HTMLAppletElementLegacyCall

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 157 matching lines @@
         InsertAdjacentText = 140,
         InsertAdjacentElement = 141,
         HasAttributes = 142, // Removed from DOM4.
         DOMSubtreeModifiedEvent = 143,
         DOMNodeInsertedEvent = 144,
         DOMNodeRemovedEvent = 145,
         DOMNodeRemovedFromDocumentEvent = 146,
         DOMNodeInsertedIntoDocumentEvent = 147,
         DOMCharacterDataModifiedEvent = 148,
         DocumentAllLegacyCall = 150,
-        HTMLAppletElementLegacyCall = 151,
+        HTMLAppletElementLegacyCall = 151, // Removed
         HTMLEmbedElementLegacyCall = 152,
         HTMLObjectElementLegacyCall = 153,
         GetMatchedCSSRules = 155,
         SVGFontInCSS = 156,
         AttributeOwnerElement = 160, // Removed in DOM4.
         AttributeSpecified = 162, // Removed in DOM4.
         PrefixedAudioDecodedByteCount = 164,
         PrefixedVideoDecodedByteCount = 165,
         PrefixedVideoSupportsFullscreen = 166,
         PrefixedVideoDisplayingFullscreen = 167,
@@ skipping 445 matching lines @@
 
     void updateMeasurements();
 
     OwnPtr<BitVector> m_countBits;
     BitVector m_CSSFeatureBits;
 };
 
 } // namespace blink
 
 #endif // UseCounter_h