Avoid to list internal Arrays in _GetRetainingPath api

runtime/vm/object_graph.cc

Index: runtime/vm/object_graph.cc
diff --git a/runtime/vm/object_graph.cc b/runtime/vm/object_graph.cc
index bbecac73b11bfdaf1717a3bf6a33c81fb8769b9e..ff20ef810dafe5dd8ccf01c5a6893868b75bc28a 100644
--- a/runtime/vm/object_graph.cc
+++ b/runtime/vm/object_graph.cc
@@ -328,13 +328,21 @@ class RetainingPathVisitor : public ObjectGraph::Visitor {
       }
     } else {
       HANDLESCOPE(thread_);
+      RawObject* object;

[Cutch, 2016/08/11 13:23:21]

It is generally unsafe to use a RawObject* you should use:

Object& object = Object::Handle();

But it looks like a new handle isn't necessary and you could just use current.

[cbernaschina, 2016/08/11 22:03:31]

Done.

       Object& current = Object::Handle();
       Smi& offset_from_parent = Smi::Handle();
+      bool isLastDartInstance = true;
       do {
+        object = it->Get();
+        if (!isLastDartInstance && object->IsArray()) {

[Cutch, 2016/08/11 13:23:21]

please document what this is testing for and why it is necessary

[cbernaschina, 2016/08/11 22:03:31]

Done.

+          isLastDartInstance = true;
+          continue;
+        }
+        isLastDartInstance = object->IsDartInstance();
         intptr_t obj_index = length_ * 2;
         intptr_t offset_index = obj_index + 1;
         if (!path_.IsNull() && offset_index < path_.Length()) {
-          current = it->Get();
+          current = object;
           path_.SetAt(obj_index, current);
           offset_from_parent = Smi::New(it->OffsetFromParentInWords());
           path_.SetAt(offset_index, offset_from_parent);