Add flag to trace object groups

src/heap/incremental-marking.h

Index: src/heap/incremental-marking.h
diff --git a/src/heap/incremental-marking.h b/src/heap/incremental-marking.h
index dd53e19301ff0c3ca1480f1b99f50235aecb2e6f..3b3ba6e0609e37be9e2b20b96ecf9548588ff8bb 100644
--- a/src/heap/incremental-marking.h
+++ b/src/heap/incremental-marking.h
@@ -105,7 +105,7 @@ class IncrementalMarking {
   void Epilogue();
 
   // Performs incremental marking steps of step_size_in_bytes as long as
-  // deadline_ins_ms is not reached. step_size_in_bytes can be 0 to compute
+  // deadline_in_ms is not reached. step_size_in_bytes can be 0 to compute
   // an estimate increment. Returns the remaining time that cannot be used
   // for incremental marking anymore because a single step would exceed the
   // deadline.