Remove duplicated headers from core/

Source/core/css/StylePropertySet.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2011 Research In Motion Limited. All rights reserved.
  * Copyright (C) 2013 Intel Corporation. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 10 matching lines @@
  */
 
 #include "config.h"
 #include "core/css/StylePropertySet.h"
 
 #include "RuntimeEnabledFeatures.h"
 #include "StylePropertyShorthand.h"
 #include "core/css/CSSParser.h"
 #include "core/css/CSSValuePool.h"
 #include "core/css/CSSVariableValue.h"
-#include "core/css/PropertySetCSSStyleDeclaration.h"
 #include "core/css/StylePropertySerializer.h"
 #include "core/css/StyleSheetContents.h"
 #include "core/page/RuntimeCSSEnabled.h"
 #include "wtf/text/StringBuilder.h"
 
 #ifndef NDEBUG
 #include "wtf/text/CString.h"
 #include <stdio.h>
 #endif
 
@@ skipping 666 matching lines @@
     result.appendLiteral(": ");
     result.append(propertyValue()->cssText());
     if (isImportant())
         result.appendLiteral(" !important");
     result.append(';');
     return result.toString();
 }
 
 
 } // namespace WebCore