Oilpan: Prepare to move RenderObject and RenderObjectChildList to Oilpan heap.

Source/core/rendering/RenderListMarker.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Andrew Wellington (proton@wiretapped.net)
  * Copyright (C) 2010 Daniel Bates (dbates@intudata.com)
  *
  * 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
@@ skipping 1049 matching lines @@
     setInline(true);   // our object is Inline
     setReplaced(true); // pretend to be replaced
 }
 
 RenderListMarker::~RenderListMarker()
 {
     if (m_image)
         m_image->removeClient(this);
 }
 
+void RenderListMarker::trace(Visitor* visitor)
+{
+    visitor->trace(m_listItem);
+    RenderBox::trace(visitor);
+}
+
 RenderListMarker* RenderListMarker::createAnonymous(RenderListItem* item)
 {
     Document& document = item->document();
     RenderListMarker* renderer = new RenderListMarker(item);
     renderer->setDocumentForAnonymous(&document);
     return renderer;
 }
 
 void RenderListMarker::styleWillChange(StyleDifference diff, const RenderStyle& newStyle)
 {
@@ skipping 757 matching lines @@
 
     if (clipToVisibleContent)
         mapRectToPaintInvalidationBacking(paintInvalidationContainer, rect);
     else
         rect = localToContainerQuad(FloatRect(rect), paintInvalidationContainer).enclosingBoundingBox();
 
     return rect;
 }
 
 } // namespace blink