Remove unused includes from various .cpp files in core/

Source/core/page/PageGroup.cpp

 /*
  * Copyright (C) 2008 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 13 matching lines @@
  */
 
 #include "config.h"
 #include "core/page/PageGroup.h"
 
 #include "core/dom/Document.h"
 #include "core/dom/DocumentStyleSheetCollection.h"
 #include "core/page/Frame.h"
 #include "core/page/GroupSettings.h"
 #include "core/page/Page.h"
-#include "core/page/Settings.h"
 #include "core/storage/StorageNamespace.h"
 
 namespace WebCore {
 
 PageGroup::PageGroup()
     : m_groupSettings(GroupSettings::create())
 {
 }
 
 PageGroup::~PageGroup()
@@ skipping 53 matching lines @@
 {
     // Clear our cached sheets and have them just reparse.
     HashSet<Page*>::const_iterator end = m_pages.end();
     for (HashSet<Page*>::const_iterator it = m_pages.begin(); it != end; ++it) {
         for (Frame* frame = (*it)->mainFrame(); frame; frame = frame->tree()->traverseNext())
             frame->document()->styleSheetCollection()->invalidateInjectedStyleSheetCache();
     }
 }
 
 } // namespace WebCore