Refactoring: Use enum class for SerializationType

Source/core/editing/MarkupAccumulator.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2009, 2010 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
@@ skipping 496 matching lines @@
         return false;
     if (element.hasChildren())
         return false;
     if (element.isHTMLElement() && !elementCannotHaveEndTag(element))
         return false;
     return true;
 }
 
 bool MarkupAccumulator::serializeAsHTMLDocument(const Node& node) const
 {
-    if (m_serializationType == ForcedXML)
+    if (m_serializationType == SerializationType::ForcedXML)
         return false;
     return node.document().isHTMLDocument();
 }
 
 template<typename Strategy>
 static void serializeNodesWithNamespaces(MarkupAccumulator& accumulator, Node& targetNode, EChildrenOnly childrenOnly, const Namespaces* namespaces)
 {
     Namespaces namespaceHash;
     if (namespaces)
         namespaceHash = *namespaces;
@@ skipping 22 matching lines @@
         namespaces = &namespaceHash;
     }
 
     serializeNodesWithNamespaces<Strategy>(accumulator, targetNode, childrenOnly, namespaces);
     return accumulator.toString();
 }
 
 template String serializeNodes<EditingStrategy>(MarkupAccumulator&, Node&, EChildrenOnly);
 
 }