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

src/api.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 6139 matching lines @@
 
 
 const HeapGraphNode* HeapSnapshot::GetNode(int index) const {
   i::Isolate* isolate = i::Isolate::Current();
   IsDeadCheck(isolate, "v8::HeapSnapshot::GetNode");
   return reinterpret_cast<const HeapGraphNode*>(
       ToInternal(this)->entries()->at(index));
 }
 
 
+SnapshotObjectId HeapSnapshot::GetMaxSnapshotJSObjectId() const {
+  i::Isolate* isolate = i::Isolate::Current();
+  IsDeadCheck(isolate, "v8::HeapSnapshot::GetMaxSnapshotJSObjectId");
+  return ToInternal(this)->max_snapshot_js_object_id();
+}
+
+
 void HeapSnapshot::Serialize(OutputStream* stream,
                              HeapSnapshot::SerializationFormat format) const {
   i::Isolate* isolate = i::Isolate::Current();
   IsDeadCheck(isolate, "v8::HeapSnapshot::Serialize");
   ApiCheck(format == kJSON,
            "v8::HeapSnapshot::Serialize",
            "Unknown serialization format");
   ApiCheck(stream->GetOutputEncoding() == OutputStream::kAscii,
            "v8::HeapSnapshot::Serialize",
            "Unsupported output encoding");
@@ skipping 189 matching lines @@
 
 
 char* HandleScopeImplementer::Iterate(ObjectVisitor* v, char* storage) {
   HandleScopeImplementer* scope_implementer =
       reinterpret_cast<HandleScopeImplementer*>(storage);
   scope_implementer->IterateThis(v);
   return storage + ArchiveSpacePerThread();
 }
 
 } }  // namespace v8::internal