Implement a heap profiler for the Dart managed heap.

runtime/vm/visitor.h

Index: runtime/vm/visitor.h
diff --git a/runtime/vm/visitor.h b/runtime/vm/visitor.h
index b259bf1e9e55c7f3e6ac0fea7ce80d05f6c2aab8..8bd2e84e3a4353c5c0750e43d6e8b273aa8f3eeb 100644
--- a/runtime/vm/visitor.h
+++ b/runtime/vm/visitor.h
@@ -29,6 +29,16 @@ class ObjectPointerVisitor {
 };
 
 
+// An object visitor interface.
+class ObjectVisitor {
+ public:
+  virtual ~ObjectVisitor() {}
+
+  // Invoked for each object.
+  virtual void VisitObject(RawObject* obj) = 0;
+};
+
+
 // An object finder visitor interface.
 class FindObjectVisitor {
  public: