Replace RenderArena with PartitionAlloc

Source/core/rendering/BidiRun.h

Index: Source/core/rendering/BidiRun.h
diff --git a/Source/core/rendering/BidiRun.h b/Source/core/rendering/BidiRun.h
index 74f3fadbf5794e4b84d5dbe2fef2ba5813087863..abfe2d1df9b03c6109762a212eec9c3cba8603b8 100644
--- a/Source/core/rendering/BidiRun.h
+++ b/Source/core/rendering/BidiRun.h
@@ -44,21 +44,13 @@ struct BidiRun : BidiCharacterRun {
         m_startsSegment = false;
     }
 
-    void destroy();
-
-    // Overloaded new operator.
-    void* operator new(size_t, RenderArena*);
-
-    // Overridden to prevent the normal delete from being called.
-    void operator delete(void*, size_t);
+    // BidiRuns are allocated out of the rendering partition.
+    void* operator new(size_t);
+    void operator delete(void*);
 
     BidiRun* next() { return static_cast<BidiRun*>(m_next); }
     RenderObject* object() { return m_object; }
 
-private:
-    // The normal operator new is disallowed.
-    void* operator new(size_t) throw();
-
 public:
     RenderObject* m_object;
     InlineBox* m_box;