Remove now-unnecessary VectorTraits specializations.

Source/core/dom/Fullscreen.h

 /*
  * 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 117 matching lines @@
 
 inline Fullscreen* Fullscreen::fromIfExists(Document& document)
 {
     if (!document.hasFullscreenSupplement())
         return 0;
     return fromIfExistsSlow(document);
 }
 
 } // namespace blink
 
-// Needed by the HeapVector<> element stack.
-namespace WTF {
-
-template<>struct IsPod<blink::Fullscreen::RequestType> {
-    static const bool value = true;
-};
-
-} // namespace WTF
-
 #endif // Fullscreen_h