Replace RenderArena with PartitionAlloc.

Source/core/rendering/RenderObject.h

Index: Source/core/rendering/RenderObject.h
diff --git a/Source/core/rendering/RenderObject.h b/Source/core/rendering/RenderObject.h
index 8cc247b2e88b57ace5c9bfb2ea62ca3a2015b3c7..3c5022f12a24b289a41a63925f481332343c5cae 100644
--- a/Source/core/rendering/RenderObject.h
+++ b/Source/core/rendering/RenderObject.h
@@ -301,19 +301,9 @@ public:
 
     static RenderObject* createObject(Element*, RenderStyle*);
 
-    // Overloaded new operator.  Derived classes must override operator new
-    // in order to allocate out of the RenderArena.
-    void* operator new(size_t, RenderArena*);
-
-    // Overridden to prevent the normal delete from being called.
-    void operator delete(void*, size_t);
-
-private:
-    // The normal operator new is disallowed on all render objects.
-    void* operator new(size_t) throw();
-
-public:
-    RenderArena* renderArena() const { return document()->renderArena(); }
+#if ENABLE(PARTITION_ALLOC)
+    void* operator new(size_t);
+#endif
 
     bool isPseudoElement() const { return node() && node()->isPseudoElement(); }
 
@@ -950,6 +940,9 @@ public:
     RespectImageOrientationEnum shouldRespectImageOrientation() const;
 
 protected:
+#if ENABLE(PARTITION_ALLOC)
+    void operator delete(void*);
+#endif
     inline bool layerCreationAllowedForSubtree() const;
 
     // Overrides should call the superclass at the end
@@ -971,7 +964,7 @@ protected:
 
     void clearLayoutRootIfNeeded() const;
     virtual void willBeDestroyed();
-    void arenaDelete(RenderArena*, void* objectBase);
+    void postDestroy();
 
     virtual bool canBeReplacedWithInlineRunIn() const;