Avoid to list internal Arrays in _GetRetainingPath api

runtime/vm/object_graph.cc

 // 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.
 
 #include "vm/object_graph.h"
 
 #include "vm/dart.h"
 #include "vm/growable_array.h"
 #include "vm/isolate.h"
 #include "vm/object.h"
@@ skipping 310 matching lines @@
 
   virtual Direction VisitObject(ObjectGraph::StackIterator* it) {
     if (it->Get() != obj_) {
       if (ShouldSkip(it->Get())) {
         return kBacktrack;
       } else {
         return kProceed;
       }
     } 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);
         }
         ++length_;
       } while (it->MoveToParent());
       return kAbort;
     }
   }
 
@@ skipping 176 matching lines @@
   {
     WritePointerVisitor ptr_writer(isolate(), stream);
     isolate()->IterateObjectPointers(&ptr_writer, false);
   }
   stream->WriteUnsigned(0);
   IterateObjects(&visitor);
   return visitor.count() + 1;  // + root
 }
 
 }  // namespace dart