Revert of [heap] Fine-grained JSArrayBuffer tracking

src/heap/heap.h

Index: src/heap/heap.h
diff --git a/src/heap/heap.h b/src/heap/heap.h
index 7f9275a842a8d2a770c767ac210548511e665cc6..12ae76583d35d72870a155eb85d4762eef5af202 100644
--- a/src/heap/heap.h
+++ b/src/heap/heap.h
@@ -815,16 +815,6 @@
     amount_of_external_allocated_memory_ += delta;
   }
 
-  void update_amount_of_external_allocated_freed_memory(intptr_t freed) {
-    amount_of_external_allocated_memory_freed_.Increment(freed);
-  }
-
-  void account_amount_of_external_allocated_freed_memory() {
-    amount_of_external_allocated_memory_ -=
-        amount_of_external_allocated_memory_freed_.Value();
-    amount_of_external_allocated_memory_freed_.SetValue(0);
-  }
-
   void DeoptMarkedAllocationSites();
 
   bool DeoptMaybeTenuredAllocationSites() {
@@ -1991,8 +1981,6 @@
 
   // Caches the amount of external memory registered at the last global gc.
   int64_t amount_of_external_allocated_memory_at_last_global_gc_;
-
-  base::AtomicNumber<intptr_t> amount_of_external_allocated_memory_freed_;
 
   // This can be calculated directly from a pointer to the heap; however, it is
   // more expedient to get at the isolate directly from within Heap methods.