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

Source/core/rendering/RenderMedia.cpp

 /*
  * Copyright (C) 2007, 2008, 2009, 2010 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 24 matching lines @@
 RenderMedia::RenderMedia(HTMLMediaElement* video)
     : RenderImage(video)
 {
     setImageResource(RenderImageResource::create());
 }
 
 RenderMedia::~RenderMedia()
 {
 }
 
+void RenderMedia::trace(Visitor* visitor)
+{
+    visitor->trace(m_children);
+    RenderImage::trace(visitor);
+}
+
 HTMLMediaElement* RenderMedia::mediaElement() const
 {
     return toHTMLMediaElement(node());
 }
 
 void RenderMedia::layout()
 {
     LayoutSize oldSize = contentBoxRect().size();
 
     RenderImage::layout();
@@ skipping 14 matching lines @@
     controlsRenderer->style()->setWidth(Length(newSize.width(), Fixed));
     controlsRenderer->forceLayout();
     clearNeedsLayout();
 }
 
 void RenderMedia::paintReplaced(PaintInfo&, const LayoutPoint&)
 {
 }
 
 } // namespace blink