I'd like to introduce kSynthetic type of nodes for Heap Profiler.

test/cctest/test-heap-profiler.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 //
 // Tests for heap profiler
 
 #include "v8.h"
 
 #include "cctest.h"
 #include "heap-profiler.h"
 #include "snapshot.h"
 #include "utils-inl.h"
@@ skipping 756 matching lines @@
   const v8::HeapSnapshot* snapshot =
       v8::HeapProfiler::TakeSnapshot(v8_str("retained"));
 
   CHECK_EQ(3, TestRetainedObjectInfo::instances.length());
   for (int i = 0; i < TestRetainedObjectInfo::instances.length(); ++i) {
     CHECK(TestRetainedObjectInfo::instances[i]->disposed());
     delete TestRetainedObjectInfo::instances[i];
   }
 
   const v8::HeapGraphNode* native_group_aaa = GetNode(
-      snapshot->GetRoot(), v8::HeapGraphNode::kNative, "aaa-group");
+      snapshot->GetRoot(), v8::HeapGraphNode::kSynthetic, "aaa-group");
   CHECK_NE(NULL, native_group_aaa);
   CHECK_EQ(1, native_group_aaa->GetChildrenCount());
   const v8::HeapGraphNode* aaa = GetNode(
       native_group_aaa, v8::HeapGraphNode::kNative, "aaa / 100 entries");
   CHECK_NE(NULL, aaa);
   CHECK_EQ(2, aaa->GetChildrenCount());
 
   const v8::HeapGraphNode* native_group_ccc = GetNode(
-      snapshot->GetRoot(), v8::HeapGraphNode::kNative, "ccc-group");
+      snapshot->GetRoot(), v8::HeapGraphNode::kSynthetic, "ccc-group");
   const v8::HeapGraphNode* ccc = GetNode(
       native_group_ccc, v8::HeapGraphNode::kNative, "ccc");
   CHECK_NE(NULL, ccc);
 
   const v8::HeapGraphNode* n_AAA = GetNode(
       aaa, v8::HeapGraphNode::kString, "AAA");
   CHECK_NE(NULL, n_AAA);
   const v8::HeapGraphNode* n_BBB = GetNode(
       aaa, v8::HeapGraphNode::kString, "BBB");
   CHECK_NE(NULL, n_BBB);
@@ skipping 427 matching lines @@
       v8::HeapProfiler::TakeSnapshot(v8_str("fun"));
   const v8::HeapGraphNode* global = GetGlobalObject(snapshot);
   CHECK_NE(NULL, global);
   const v8::HeapGraphNode* fun =
       GetProperty(global, v8::HeapGraphEdge::kShortcut, "fun");
   CHECK(HasWeakEdge(fun));
   const v8::HeapGraphNode* shared =
       GetProperty(fun, v8::HeapGraphEdge::kInternal, "shared");
   CHECK(HasWeakEdge(shared));
 }