Retained size for instance in Observatory.

runtime/vm/object_graph.h

 // Copyright (c) 2014, 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_OBJECT_GRAPH_H_
 #define VM_OBJECT_GRAPH_H_
 
 #include "vm/object.h"
 
 namespace dart {
@@ skipping 43 matching lines @@
   ~ObjectGraph();
 
   // Visits all strongly reachable objects in the isolate's heap, in a
   // pre-order, depth first traversal.
   void IterateObjects(Visitor* visitor);
 
   // Like 'IterateObjects', but restricted to objects reachable from 'root'
   // (including 'root' itself).
   void IterateObjectsFrom(const Object& root, Visitor* visitor);
 
+  // The number of bytes retained by 'obj'.
+  intptr_t SizeRetainedByInstance(const Object& obj);
+
+  // The number of bytes retained by the set of all objects of the given class.
+  intptr_t SizeRetainedByClass(intptr_t class_id);
+
  private:
   Isolate* isolate_;
   DISALLOW_IMPLICIT_CONSTRUCTORS(ObjectGraph);
 };
 
 }  // namespace dart
 
 #endif  // VM_OBJECT_GRAPH_H_