Current schema of calculation max_snapshot_js_object_id is not always correct.

src/profile-generator.cc

Index: src/profile-generator.cc
diff --git a/src/profile-generator.cc b/src/profile-generator.cc
index acab8a092f1a81d999af7bc94160bb057d14d4dd..2315fc53884cb7530f672edc096602cdcbe88269 100644
--- a/src/profile-generator.cc
+++ b/src/profile-generator.cc
@@ -1158,6 +1158,11 @@ void HeapSnapshot::Delete() {
 }
 
 
+void HeapSnapshot::RememberLastJSObjectId() {
+  max_snapshot_js_object_id_ = collection_->last_assigned_id();
+}
+
+
 void HeapSnapshot::AllocateEntries(int entries_count,
                                    int children_count,
                                    int retainers_count) {
@@ -1224,11 +1229,6 @@ HeapEntry* HeapSnapshot::AddEntry(HeapEntry::Type type,
                                   int retainers_count) {
   HeapEntry* entry = GetNextEntryToInit();
   entry->Init(this, type, name, id, size, children_count, retainers_count);
-
-  // Track only js objects. They have odd ids.
-  if (id % HeapObjectsMap::kObjectIdStep && id > max_snapshot_js_object_id_)
-    max_snapshot_js_object_id_ = id;
-
   return entry;
 }
 
@@ -3111,6 +3111,8 @@ bool HeapSnapshotGenerator::GenerateSnapshot() {
   // Pass 2. Fill references.
   if (!FillReferences()) return false;
 
+  snapshot_->RememberLastJSObjectId();
+
   if (!SetEntriesDominators()) return false;
   if (!CalculateRetainedSizes()) return false;