Replace RenderArena with PartitionAlloc.

Source/core/rendering/RenderWidgetProtector.h

 /*
  * Copyright (C) 2009 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 12 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef RenderWidgetProtector_h
 #define RenderWidgetProtector_h
 
 #include "core/rendering/RenderWidget.h"
 
 namespace WebCore {
 
 class RenderWidgetProtector {

[abarth-chromium, 2013/06/20 01:39:50]

Isn't this just a RefPtr now?

     WTF_MAKE_NONCOPYABLE(RenderWidgetProtector);
 public:
     explicit RenderWidgetProtector(RenderWidget* object)
         : m_object(object)
-        , m_arena(object->ref())
     {
+        m_object->ref();
     }
 
     ~RenderWidgetProtector()
     {
-        m_object->deref(m_arena);
+        m_object->deref();
     }
 
 private:
     RenderWidget* m_object;
-    RenderArena* m_arena;
 };
 
 }
 
 #endif // RenderWidgetProtector_h