Use the zone in ApiNativeScope for allocating objects in the ApiMessageReader instead of passing in…

runtime/vm/dart_api_message.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_DART_API_MESSAGE_H_
 #define VM_DART_API_MESSAGE_H_
 
 #include "include/dart_native_api.h"
 #include "vm/dart_api_state.h"
 #include "vm/snapshot.h"
@@ skipping 23 matching lines @@
       int offset_in_bytes;
       int length;
     } as_view;
   } internal;
 };
 
 
 // Reads a message snapshot into a C structure.
 class ApiMessageReader : public BaseReader {
  public:
-  // The allocator passed is used to allocate memory for the C structure used
-  // to represent the message snapshot. This allocator must keep track of the
-  // memory allocated as there is no way to run through the resulting C
-  // structure and free the individual pieces. Using a zone based allocator is
-  // recommended.
-  ApiMessageReader(const uint8_t* buffer,
-                   intptr_t length,
-                   ReAlloc alloc);
+  // The ApiMessageReader object must be enclosed by an ApiNativeScope.
+  // Allocation of all C Heap objects is done in the zone associated with
+  // the enclosing ApiNativeScope.
+  ApiMessageReader(const uint8_t* buffer, intptr_t length);
   ~ApiMessageReader() { }
 
   Dart_CObject* ReadMessage();
 
  private:
   class BackRefNode {
    public:
     BackRefNode(Dart_CObject* reference, DeserializeState state)
         : reference_(reference), state_(state) {}
     Dart_CObject* reference() const { return reference_; }
@@ skipping 70 matching lines @@
   }
 
   RawObject* VmIsolateSnapshotObject(intptr_t index) const {
     return Object::vm_isolate_snapshot_object_table().At(index);
   }
 
   Dart_CObject* CreateDartCObjectString(RawObject* raw);
   Dart_CObject* GetCanonicalMintObject(Dart_CObject_Type type,
                                        int64_t value64);
 
-  // Allocation of the structures for the decoded message happens
-  // either in the supplied zone or using the supplied allocation
-  // function.
-  ReAlloc alloc_;
+  uint8_t* allocator(intptr_t size) {
+    return zone_->Realloc<uint8_t>(NULL, 0, size);
+  }
+
+  Zone* zone_;  // Zone in which C heap objects are allocated.
   ApiGrowableArray<BackRefNode*> backward_references_;
   ApiGrowableArray<Dart_CObject*> vm_isolate_references_;
   Dart_CObject** vm_symbol_references_;
 
   Dart_CObject type_arguments_marker;
   Dart_CObject dynamic_type_marker;
   static _Dart_CObject* singleton_uint32_typed_data_;
 };
 
 
@@ skipping 44 matching lines @@
   Dart_CObject** forward_list_;
   intptr_t forward_list_length_;
   intptr_t forward_id_;
 
   DISALLOW_COPY_AND_ASSIGN(ApiMessageWriter);
 };
 
 }  // namespace dart
 
 #endif  // VM_DART_API_MESSAGE_H_