Oilpan: add reqd tracing of ImportedStyleSheetClients.

third_party/WebKit/Source/core/css/StyleRuleImport.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * (C) 2002-2003 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2002, 2005, 2006, 2008, 2009, 2010, 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.
  *
@@ skipping 43 matching lines @@
 #if !ENABLE(OILPAN)
     if (m_styleSheet)
         m_styleSheet->clearOwnerRule();
 #endif
     if (m_resource)
         m_resource->removeClient(&m_styleSheetClient);
 }
 
 DEFINE_TRACE_AFTER_DISPATCH(StyleRuleImport)
 {
+    visitor->trace(m_styleSheetClient);
     visitor->trace(m_parentStyleSheet);
     visitor->trace(m_mediaQueries);
     visitor->trace(m_styleSheet);
     StyleRuleBase::traceAfterDispatch(visitor);
 }
 
 void StyleRuleImport::setCSSStyleSheet(const String& href, const KURL& baseURL, const String& charset, const CSSStyleSheetResource* cachedStyleSheet)
 {
     if (m_styleSheet)
         m_styleSheet->clearOwnerRule();
@@ skipping 61 matching lines @@
         // removed from the pending sheet count, so let the doc know
         // the sheet being imported is pending.
         if (m_parentStyleSheet && m_parentStyleSheet->loadCompleted() && rootSheet == m_parentStyleSheet)
             m_parentStyleSheet->startLoadingDynamicSheet();
         m_loading = true;
         m_resource->addClient(&m_styleSheetClient);
     }
 }
 
 } // namespace blink