Remove Apple's unused implementation of private browsing from WebCore

Source/WebCore/rendering/RenderSearchField.cpp

 /**
  * Copyright (C) 2006, 2007, 2010 Apple Inc. All rights reserved.
  *           (C) 2008 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/) 
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 73 matching lines @@
 void RenderSearchField::addSearchResult()
 {
     HTMLInputElement* input = inputElement();
     if (input->maxResults() <= 0)
         return;
 
     String value = input->value();
     if (value.isEmpty())
         return;
 
-    Settings* settings = document()->settings();
-    if (!settings || settings->privateBrowsingEnabled())
-        return;
-
     int size = static_cast<int>(m_recentSearches.size());
     for (int i = size - 1; i >= 0; --i) {
         if (m_recentSearches[i] == value)
             m_recentSearches.remove(i);
     }
 
     m_recentSearches.insert(0, value);
     while (static_cast<int>(m_recentSearches.size()) > input->maxResults())
         m_recentSearches.removeLast();
 
@@ skipping 268 matching lines @@
     if (containerRenderer->logicalHeight() <= contentLogicalHeight())
         return;
 
     // A quirk for find-in-page box on Safari Windows.
     // http://webkit.org/b/63157
     LayoutUnit logicalHeightDiff = containerRenderer->logicalHeight() - contentLogicalHeight();
     containerRenderer->setLogicalTop(containerRenderer->logicalTop() - (logicalHeightDiff / 2 + layoutMod(logicalHeightDiff, 2)));
 }
 
 }