Repeatedly overapproximate the weak closure as long as we make progress

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index 913ac13d43832494e2234c123e6e421e2074cc6e..ae2f0dc13c1961d5c8669fd22e257a34ed228c27 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -766,6 +766,10 @@ void Heap::OverApproximateWeakClosure(const char* gc_reason) {
     PrintF("[IncrementalMarking] Overapproximate weak closure (%s).\n",
            gc_reason);
   }
+
+  GCTracer::Scope gc_scope(tracer(),
+                           GCTracer::Scope::MC_INCREMENTAL_WEAKCLOSURE);
+
   {
     GCCallbacksScope scope(this);
     if (scope.CheckReenter()) {