Should remove StyleSheetContents from cache even if document is not active.

Source/core/css/StyleSheetContents.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2006, 2007, 2012 Apple Inc. All rights reserved.
  *
  * 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 570 matching lines @@
 
 void StyleSheetContents::clientLoadStarted(CSSStyleSheet* sheet)
 {
     ASSERT(m_completedClients.contains(sheet));
     m_completedClients.remove(sheet);
     m_loadingClients.add(sheet);
 }
 
 void StyleSheetContents::removeSheetFromCache(Document* document)
 {
+    ASSERT(document);
     if (!maybeCacheable())
         return;
-    if (!document || !document->isActive())
-        return;
     document->styleEngine()->removeSheet(this);
 }
 
 void StyleSheetContents::addedToMemoryCache()
 {
     ASSERT(!m_isInMemoryCache);
     ASSERT(isCacheable());
     m_isInMemoryCache = true;
 }
 
@@ skipping 91 matching lines @@
 {
     visitor->trace(m_ownerRule);
     visitor->trace(m_importRules);
     visitor->trace(m_childRules);
     visitor->trace(m_loadingClients);
     visitor->trace(m_completedClients);
     visitor->trace(m_ruleSet);
 }
 
 }