Revert of Replaced different means of zone pooling/reusing by one zone segment pool

src/zone/zone.h

Index: src/zone/zone.h
diff --git a/src/zone/zone.h b/src/zone/zone.h
index 3f37942e7c48b15ff5e2530833c967149bda071f..752a03564b640103e36f8ae7ebbce3ea431c8db7 100644
--- a/src/zone/zone.h
+++ b/src/zone/zone.h
@@ -44,6 +44,9 @@
     return static_cast<T*>(New(length * sizeof(T)));
   }
 
+  // Deletes all objects and free all memory allocated in the Zone.
+  void DeleteAll();
+
   // Returns true if more memory has been allocated in zones than
   // the limit allows.
   bool excess_allocation() const {
@@ -74,9 +77,6 @@
   // Report zone excess when allocation exceeds this limit.
   static const size_t kExcessLimit = 256 * MB;
 
-  // Deletes all objects and free all memory allocated in the Zone.
-  void DeleteAll();
-
   // The number of bytes allocated in this zone so far.
   size_t allocation_size_;
 
@@ -123,6 +123,19 @@
   // Zone::DeleteAll() to delete all zone objects in one go.
   void operator delete(void*, size_t) { UNREACHABLE(); }
   void operator delete(void* pointer, Zone* zone) { UNREACHABLE(); }
+};
+
+// The ZoneScope is used to automatically call DeleteAll() on a
+// Zone when the ZoneScope is destroyed (i.e. goes out of scope)
+class ZoneScope final {
+ public:
+  explicit ZoneScope(Zone* zone) : zone_(zone) {}
+  ~ZoneScope() { zone_->DeleteAll(); }
+
+  Zone* zone() const { return zone_; }
+
+ private:
+  Zone* zone_;
 };
 
 // The ZoneAllocationPolicy is used to specialize generic data