Replace RenderArena with PartitionAlloc.

Source/core/html/HTMLCanvasElement.h

 /*
  * Copyright (C) 2004, 2006, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. 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.
@@ skipping 119 matching lines @@
     bool shouldAccelerate(const IntSize&) const;
 
     float deviceScaleFactor() const { return m_deviceScaleFactor; }
 
     virtual void reportMemoryUsage(MemoryObjectInfo*) const OVERRIDE;
 
 private:
     HTMLCanvasElement(const QualifiedName&, Document*);
 
     virtual void parseAttribute(const QualifiedName&, const AtomicString&) OVERRIDE;
-    virtual RenderObject* createRenderer(RenderArena*, RenderStyle*);
+    virtual RenderObject* createRenderer(RenderStyle*);
     virtual void attach(const AttachContext& = AttachContext()) OVERRIDE;
     virtual bool areAuthorShadowsAllowed() const OVERRIDE { return false; }
 
     void reset();
 
     float targetDeviceScaleFactor() const;
 
     void createImageBuffer() const;
     void clearImageBuffer() const;
 
@@ skipping 21 matching lines @@
     mutable OwnPtr<ImageBuffer> m_imageBuffer;
     mutable OwnPtr<GraphicsContextStateSaver> m_contextStateSaver;
     
     mutable RefPtr<Image> m_presentedImage;
     mutable RefPtr<Image> m_copiedImage; // FIXME: This is temporary for platforms that have to copy the image buffer to render (and for CSSCanvasValue).
 };
 
 } //namespace
 
 #endif