Componentization: fix SupplementTracing<0>::~SupplementTracing<0>(void) already defined.

Source/core/dom/DocumentSupplementable.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 10 matching lines @@
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  *
  */
 
 #ifndef DocumentSupplementable_h
 #define DocumentSupplementable_h
 
+#include "core/CoreExport.h"
 #include "platform/Supplementable.h"
 
 namespace blink {
 
 class Document;
 
+extern template class CORE_TEMPLATE_EXPORT WillBeHeapSupplement<Document>;
+
 using DocumentSupplementable = WillBeHeapSupplementable<Document>;
 using DocumentSupplement = WillBeHeapSupplement<Document>;

[haraken, 2015/04/22 05:26:53]

Not related to your CL, we want to remove these two usings, since other
supplementable classes don't have the usings. We can just use
WillBeHeapSupplement<Document> in the call sites.

If we remove these usings, the extern declaration could go to Document.h. Then
we can remove this file.

[tasak, 2015/04/22 06:59:37]

Removed DocumentSupplementable.h.

 
 } // namespace blink
 
 #endif // DocumentSupplementable_h