Clean up forward declarations in Source/core/accessibility

Source/core/accessibility/AXObjectCache.h

 /*
  * Copyright (C) 2003, 2006, 2007, 2008, 2009, 2010, 2011 Apple 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 19 matching lines @@
 #include "core/rendering/RenderText.h"
 #include "platform/Timer.h"
 #include "wtf/Forward.h"
 #include "wtf/HashMap.h"
 #include "wtf/HashSet.h"
 #include "wtf/RefPtr.h"
 
 namespace blink {
 
 class AbstractInlineTextBox;
-class Document;
 class HTMLAreaElement;
-class Node;
-class Page;
-class RenderObject;
 class ScrollView;
-class Settings;
-class VisiblePosition;
 class Widget;
 
 struct TextMarkerData {
     AXID axID;
     Node* node;
     int offset;
     EAffinity affinity;
 };
 
 class AXComputedObjectAttributeCache {
@@ skipping 175 matching lines @@
     Settings* settings();
 };
 
 bool nodeHasRole(Node*, const String& role);
 // This will let you know if aria-hidden was explicitly set to false.
 bool isNodeAriaVisible(Node*);
 
 }
 
 #endif