Remove Apple's unused implementation of private browsing from WebCore

Source/WebCore/dom/Document.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
@@ skipping 924 matching lines @@
     void unregisterForPageCacheSuspensionCallbacks(Element*);
 
     void documentWillBecomeInactive();
     void documentWillSuspendForPageCache();
     void documentDidResumeFromPageCache();
 
     void registerForMediaVolumeCallbacks(Element*);
     void unregisterForMediaVolumeCallbacks(Element*);
     void mediaVolumeDidChange();
 
-    void registerForPrivateBrowsingStateChangedCallbacks(Element*);
-    void unregisterForPrivateBrowsingStateChangedCallbacks(Element*);
     void storageBlockingStateDidChange();
-    void privateBrowsingStateDidChange();
 
 #if ENABLE(VIDEO_TRACK)
     void registerForCaptionPreferencesChangedCallbacks(Element*);
     void unregisterForCaptionPreferencesChangedCallbacks(Element*);
     void captionPreferencesChanged();
 #endif
 
     void setShouldCreateRenderers(bool);
     bool shouldCreateRenderers();
 
@@ skipping 462 matching lines @@
     bool m_annotatedRegionsDirty;
 
     HashMap<String, RefPtr<HTMLCanvasElement> > m_cssCanvasElements;
 
     bool m_createRenderers;
     bool m_inPageCache;
     Vector<IconURL> m_iconURLs;
 
     HashSet<Element*> m_documentSuspensionCallbackElements;
     HashSet<Element*> m_mediaVolumeCallbackElements;
-    HashSet<Element*> m_privateBrowsingStateChangedElements;
 #if ENABLE(VIDEO_TRACK)
     HashSet<Element*> m_captionPreferencesChangedElements;
 #endif
 
     HashMap<StringImpl*, Element*, CaseFoldingHash> m_elementsByAccessKey;
     bool m_accessKeyMapValid;
 
     OwnPtr<SelectorQueryCache> m_selectorQueryCache;
 
     bool m_useSecureKeyboardEntryWhenActive;
@@ skipping 161 matching lines @@
     trackForDebugging();
 #endif
     InspectorCounters::incrementCounter(InspectorCounters::NodeCounter);
 }
 
 Node* eventTargetNodeForDocument(Document*);
 
 } // namespace WebCore
 
 #endif // Document_h