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

Source/core/dom/ContextFeatures.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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 10 matching lines @@
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef ContextFeatures_h
 #define ContextFeatures_h
 
 #include "core/CoreExport.h"
+#include "core/page/Page.h"
 #include "platform/RefCountedSupplement.h"
 
 namespace blink {
 
 class ContextFeaturesClient;
 class Document;
 class Page;
 
 #if ENABLE(OILPAN)
 class ContextFeatures final : public GarbageCollectedFinalized<ContextFeatures>, public HeapSupplement<Page> {
@@ skipping 66 matching lines @@
     // See issue 294180
     //
     // if (m_client)
     //     return;
     // m_client->urlDidChange(document);
 }
 
 } // namespace blink
 
 #endif // ContextFeatures_h