Move StyleSheetResourceClient to Oilpan heap

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

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * (C) 2002-2003 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2002, 2006, 2008, 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 40 matching lines @@
 
     void requestStyleSheet();
 
     DECLARE_TRACE_AFTER_DISPATCH();
 
 private:
     // FIXME: inherit from StyleSheetResourceClient directly to eliminate back pointer, as there are no space savings in this.
     // NOTE: We put the StyleSheetResourceClient in a member instead of inheriting from it
     // to avoid adding a vptr to StyleRuleImport.
     class ImportedStyleSheetClient final : public GarbageCollectedFinalized<ImportedStyleSheetClient>, public StyleSheetResourceClient {
+        USING_GARBAGE_COLLECTED_MIXIN(ImportedStyleSheetClient);
     public:
         ImportedStyleSheetClient(StyleRuleImport* ownerRule) : m_ownerRule(ownerRule) { }
         ~ImportedStyleSheetClient() override { }
         void setCSSStyleSheet(const String& href, const KURL& baseURL, const String& charset, const CSSStyleSheetResource* sheet) override
         {
             m_ownerRule->setCSSStyleSheet(href, baseURL, charset, sheet);
         }
         String debugName() const override { return "ImportedStyleSheetClient"; }
 
         DEFINE_INLINE_TRACE()
         {
             visitor->trace(m_ownerRule);
+            StyleSheetResourceClient::trace(visitor);
         }
 
     private:
         Member<StyleRuleImport> m_ownerRule;
     };
 
     void setCSSStyleSheet(const String& href, const KURL& baseURL, const String& charset, const CSSStyleSheetResource*);
 
     StyleRuleImport(const String& href, MediaQuerySet*);
 
     void dispose();
 
     Member<StyleSheetContents> m_parentStyleSheet;
 
     Member<ImportedStyleSheetClient> m_styleSheetClient;
     String m_strHref;
     Member<MediaQuerySet> m_mediaQueries;
     Member<StyleSheetContents> m_styleSheet;
     Member<CSSStyleSheetResource> m_resource;
     bool m_loading;
 };
 
 DEFINE_STYLE_RULE_TYPE_CASTS(Import);
 
 } // namespace blink
 
 #endif