blink: Cleanup core class forward declarations

third_party/WebKit/Source/core/dom/shadow/FlatTreeTraversal.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 19 matching lines @@
 #include "core/CoreExport.h"
 #include "core/dom/Document.h"
 #include "core/dom/LayoutTreeBuilderTraversal.h"
 #include "core/dom/shadow/InsertionPoint.h"
 #include "core/dom/shadow/ShadowRoot.h"
 #include "wtf/Allocator.h"
 
 namespace blink {
 
 class ContainerNode;
-class HTMLSlotElement;
 class Node;
 
 // Flat tree version of |NodeTraversal|.
 //
 // None of member functions takes a |ShadowRoot| or an active insertion point,
 // e.g. roughly speaking <content> and <shadow> in the shadow tree, see
 // |InsertionPoint::isActive()| for details of active insertion points, since
 // they aren't appeared in the flat tree. |assertPrecondition()| and
 // |assertPostCondition()| check this condition.
 //
@@ skipping 242 matching lines @@
   return traverseChild(node, TraversalDirectionForward);
 }
 
 inline Node* FlatTreeTraversal::traverseLastChild(const Node& node) {
   return traverseChild(node, TraversalDirectionBackward);
 }
 
 }  // namespace blink
 
 #endif