Introduce StyledMarkupTraverser to StyledMarkupSerializer

Source/core/editing/StyledMarkupSerializer.h

Index: Source/core/editing/StyledMarkupSerializer.h
diff --git a/Source/core/editing/StyledMarkupSerializer.h b/Source/core/editing/StyledMarkupSerializer.h
index 5125754450c15155a5bf0290909e4e16fd77c900..9419750ac7e7cfc6ae612a441a2ea069ba5f2703 100644
--- a/Source/core/editing/StyledMarkupSerializer.h
+++ b/Source/core/editing/StyledMarkupSerializer.h
@@ -38,8 +38,6 @@
 
 namespace blink {
 
-enum class ConvertBlocksToInlines;
-
 template<typename Strategy>
 class StyledMarkupSerializer final {
     STACK_ALLOCATED();
@@ -50,16 +48,7 @@ public:
     String createMarkup();
 
 private:
-    bool convertBlocksToInlines() const { return m_convertBlocksToInlines == ConvertBlocksToInlines::Convert; }
     bool shouldAnnotate() const { return m_shouldAnnotate == AnnotateForInterchange; }
-    Node* serializeNodes(Node* startNode, Node* pastEnd, StyledMarkupAccumulator*);
-    Node* traverseNodesForSerialization(Node* startNode, Node* pastEnd, StyledMarkupAccumulator*);
-    void wrapWithNode(StyledMarkupAccumulator&, ContainerNode&, PassRefPtrWillBeRawPtr<EditingStyle>);
-    RefPtrWillBeRawPtr<EditingStyle> createInlineStyle(Element&);
-    RefPtrWillBeRawPtr<EditingStyle> createInlineStyleIfNeeded(Node&);
-    bool needsInlineStyle(const Element&);
-    void appendStartMarkup(StyledMarkupAccumulator&, Node&);
-    bool shouldApplyWrappingStyle(const Node&) const;
 
     const PositionType m_start;
     const PositionType m_end;