I'd like to add HeapSnapshot::GetMaxSnapshotJSObjectId function.

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 706cfa0ae239e47479e225c6a88acc53bb2f0e0c..3a86140cc41b4efc9797bfe06b55c07a86ab0232 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -6157,6 +6157,11 @@ const HeapGraphNode* HeapSnapshot::GetNode(int index) const {
 }
 
 
+SnapshotObjectId HeapSnapshot::GetMaxSnapshotJSObjectId() const {
+  return ToInternal(this)->max_snapshot_js_object_id();
+}
+
+
 void HeapSnapshot::Serialize(OutputStream* stream,
                              HeapSnapshot::SerializationFormat format) const {
   i::Isolate* isolate = i::Isolate::Current();